R1a frequency, subclades and origin of Croats and South Slavs

In this article are analyzed the frequencies, variance and (sub)clades of R1a among Croats and neighboring South Slavic countries & nations on 23, 21 and 17 Y-STR markers; the number of duplicate haplotypes as an indicator of heterogenity & founder effect within a population; the number of exact and 1-step-neighbor haplotype matches between populations as well as Southwestern Slavic populations with West and East Slavic populations on 17 Y-STR marker haplotypes from scientific studies; analysis of terminal subclade Y-SNP in the phylogenetic tree confirmed by NGS/WGS testing and more. In the analysis are used Nevgen predictor (which data until now confirmed that the general R1a (sub)clades can be predicted with very good probability) and GenAlEx.

1. Analysis on 23 and 21 Y-STR markers

First were analyzed haplotypes with 23 or 21 Y-STR markers to get a more reliable prediction of R1a subclades. The analysis was on 239 samples from Purps et al. 2014, including samples from the capital city of Zagreb (114) and general Croatia (125).

Out of them 31 and 26 respectively belonged to R1a, making frequency of 27.18% and 21% while the overall frequency of combined populations for Croatia, with a reliable sample size (>200), is 23.82%. 

Interestingly, the majority of R1a's frequency belonges to clade R-Z280/M558 (19.24%), followed by other two main clades R-M458 (3.34%) and R-Z93 (0.81%), and as will be seen later, almost never by some other clade (0.41%, only in this study was found one case of R-YP1051). The percentage ratio share of clades on R1a level would be R-Z280/M558 (80.7%), R-M458 (14%), R-Z93 (3.5%) and other (1.8%). 

The subclades of R-Z280/M558 were found to be relatively diverse (7), each one of them having more or less low frequency compared to total population sample size, but on the level i.e. sample size of R-Z280/M558 the ratio share is steadily and mainly made by first 4 subclades (85%), from more to less:

1. R-Z282 > Z280 > CTS1211/M558 > Y35 > CTS3402 > Y33 > CTS8816 > Y1392/Y2902 (TMRCA 2100 YBP)

2. R-Z282 > Z280 > CTS1211/M558 > Y35 > CTS3402 > Y2613 (TMRCA 2700 YBP)

3. R-Z282 > Z280 > CTS1211/M558 > YP343 (TMRCA 3900/3100 YBP)

4. R-Z282 > Z280 > CTS1211/M558 > Y35 > CTS3402 > Y33 > CTS8816 > Y3301 > L1280 (TMRCA 2300 YBP)

5. R-Z282 > Z280 > CTS1211/M558 > Y35 > CTS3402 > YP237 > FGC13681 > YP953 (TMRCA 3100/2700 YBP)

6. R-Z282 > Z280 > Z92 > Y4459 (TMRCA 3700 YBP)

7. R-Z282 > Z280 > CTS1211/M558 > Y35 > YP4278 (TMRCA 1700 YBP)

The subclades of R-M458 were divided into two of them out of which first made the majority:

1. R-Z282 > PF6155 > M458 > PF7521 > Y2604 > L260 (TMRCA 2600 YBP)

2. R-Z282 > PF6155 > M458 > PF7521 > Y2604 > FGC2608 > CTS11962 > L1029 (TMRCA 2100 YBP)

As for rare clade R-Z93, the predicted subclades were R-Z93>Y34305 and R-Z93>Z94>Z2123>Y2632, while on 17 Y-STR markers were also predicted Z93>YP1451, Z93>FT369724, Z94>S23592, Z94>L657>Y5, Z94>BY32037, Z94>Z2122>Y57, Z94> Z2122>BY48287, Z2123>YP4907, Z2123>Y934>YP451, Z2123>Y934>BY30762 and Z2123>Y934>Y7094. There won't be much discussion about them due to very low frequnecies, often low prediction reliability mistaking them with other clades, besides saying that most probably are traces of Sarmatian origin since the times of Huns and Avars in Pannonia and that, with other multidisciplinary conclusions, rejects both Iranian and Avar-Turkic origin of Croats during the early medieval migrations of the Slavs to the Balkans.

Zagreb and Croatia - Purps et al. 2014 on 23 Y-STR

To confirm the expected subclades list for the later analysis of haplotypes with 17 Y-STR markers were also analyzed population samples of neighboring countries & nations with 23 and 27 (21) Y-STR markers: samples from Slovenian capital city of Ljubljana (R1a 26/103) from Purps et al. 2014 and Slovenia (64/201) from Drobnic & Hadzic 2017 (YHRD - YA005983); Bosnian and Herzegovinian city of Tuzla (23/100) from Babić & Dogan et al. 2016 and Bosnia and Herzegovina (16/100) from Purps et al. 2014; Serbia (34/209) from Zgonjanin et al. 2017 and Western Balkans Serbs (44/303) from Kačar et al. 2019.

In the observed populations frequency of R1a is: Zagreb+Croatia (23.82%), Ljubljana (25.23%), Slovenia (31.83%) and combined Ljubljana+Slovenia (29.59%), Tuzla (23%), Bosnia and Herzegovina (16%) and combined Tuzla+Bosnia and Herzegovina (19.5%), Serbia (15.78%) and Western Balkans Serbs (14.85%), with an obvious north-south inclination. In all the populations R-Z280/M558 made the vast majority of R1a percentage (roughly 70-85%) with the exception of Western Balkans Serbs (55-65%), with absence or very low frequencies of R-Z93 and was not found other R1a clade.

On a sub-clade level of R-Z280/M558 were additionally found eight subclades:

8. R-Z282 > Z280 > CTS1211/M558 > Y35 > CTS3402 > YP237 > YP235 > YP234 > YP295> L366 (TMRCA 2200 YBP)

9. R-Z282 > Z280 > R-Z92 > Z685 > YP271 > YP270 (TMRCA 3100 YBP)

10. R-Z282 > Z280 > CTS1211/M558 > Y35 > CTS3402 > YP237 > FGC13681 > YP582 (TMRCA 2300 YBP)

11. R-Z282 > Z280 > CTS1211/M558 > FT92022 > YP1034 (TMRCA 3900 YBP)

12. R-Z282 > Z280 > CTS1211/M558 > Y35 > R-CTS3402 > R-Y33 > FT14137/Y167503 (TMRCA 3200 YBP)

13. R-Z282 > Z280 > CTS1211/M558 > Y35 > CTS3402 > YP237 > FGC13681 > YP420 (TMRCA 2900 YBP)

14. R-Z282 > Z280 > CTS1211/M558 > Y10805 (TMRCA 4400 YBP)

15. R-Z282 > Z280 > R-YP6213/YP6228 (TMRCA 1200-500 YBP)

On a sub-clade level of R-Z280/M458 was additionally found one subclade:

3. R-Z282 > PF6155 > M458 > R-A11460 (TMRCA 2600 YBP)

Regarding subclades of R-Z280/M558, the populations of Croatia and Slovenia have almost identical distribution of (main) subclades, followed by Serbia (with a bit lower R-YP343 and higher R-L1280 and R-YP953) and then population of Tuzla+Bosnia and Herzegovina (no R-Y1392/Y2902, low or no R-YP343 and very high R-L1280). In Underhill et al. 2014 were also found 2 Bosnian with no ethnic designation (both R-L1280), and 5 West Herzegovinian Croat (four R-YP953, one R-S24902 or R-CTS3402, no R-L1280), samples respectively. The general population of Bosnia and Herzegovina needs further testing and divided by ethnic groups and regions, definetly the subclade R-L1280(>Y5647) has very high concentration in northeast Bosnia and northwest Serbia (Lower Podrinje). According to its updated analysis of 141 samples from West Herzegovina Croats (originally from Peričić et al. 2005), were found 16 samples of R1a (11.3%) divided between R-MZ280/M558 (14), R-M458 (1) and R-Z282 (1).

Western Balkans Serbs (no R-L1280 and high R-YP4278 and R-YP270), and one population of Slovenia, seemingly had highest variance of subclades. In population of Slovenia possibly was also found subclade R-CTS8816 > S18681 (2; TMRCA 2500 YBP), but it is uncertain because both haplotypes have higher probability to be a R-Z93 subclade.

Regarding subclades of R-M458, the populations of Croatia and Slovenia had more or equal percentage of R-L260 compared to R-L1029, while to the contrary Bosnian and Herzegovinian and Serbian populations had more or almost exclusively R-L1029 with some R-A11460.

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian populations on 23 Y-STR

The newly found subclades have low number of haplotypes and are often absent in several populations. Some of them in later analysis of haplotypes with 17 markers are sometimes possibly confused by Nevgen calculator for other subclades, for example R-YP270 with R-YP343, R-Y10805 with R-Y1392/Y2902 and R-YP582 and R-L1280, R-YP1034 with R-Y1392/Y2902. On the 17 markers rarely show up also other subclades with low probability and confused for other second in other subclades, for example R-YP5000 with R-Y1392/Y2902 and R-YP343 or R-YP270, R-YP1019 with R-Y2613, R-YP5917 with R-Y1392/Y2902, R-YP6228 with R-Y1392/Y2902, and R-Z1907 with R-Y1392/Y2902. In such cases, aside R-YP270 and R-YP1034, will be later on 17 markers of Croatian regional populations shown two tables with and without corrected list of subclades and number of haplotypes per subclade.

During the analysis and mostly of haplotypes with 21 Y-STR markers (DYS549 and DYS643 aren't covered in the Yfiler® Plus kit with 27 markers) were found first (in Serbian populations), but very rare, signs of uncertainty of haplotype prediction at Nevgen calculator. Mostly was the case of confusing R-Z280/M558 (sub)clade with R-Z93 and more rarely R-M458 with R-Z93 (or R-Z280/M558, usually R-Y2613). Instead of counting the first result of the prediction to one of the three clade, such haplotypes were counted to each of the possibly predicted clades & subclades, making an interval of minimum and maximum number of haplotypes and percentages respectively for sake of neutrality. The same will be done in later analysis of haplotypes with 17 markers because such cases are more common. Also, sometimes while on later 17 marker much more often, were listed in prediction alongside R-Z280 (sub)clades the Scandinavian-British subclades "R-282 > Y2395 > Z284 > L448" and "R-CTS4385 > L664" or other foreign like Z282>Y17491, absent in the Balkans, which are mistaken for R-Z280 (sub)clades (mostly R-Y2613, R-CTS8816 etc.) hence needing a correction and immediate calculation with known SNP level (R-Z280).

2.1 Analysis on 17 Y-STR markers

First were re-analyzed R1a 17 Y-STR haplotypes of Zagreb + Croatia and Bosnia and Herzegovina (96) to see for how many will be confirmed previous prediction of a subclade and sub-subclade of 23 Y-STR markers. It was found out that prediction is almost the same for clade (96-97%), with 9-11% mistaken subclades and 14% sub-subclades. The first listed R-Z280/M558 subclade should be correct, R-M458>L260/L1029 easly predicts but sometimes mistakes order of the first three sub-subclades, R-Z93 should be easily predicted but sometimes is confused with R-Z280 subclades, hence comes in handy using minimum and maximum number of haplotypes for given clade, subclade and sub-subclade.

Then were analyzed 1100 samples with 17 Y-STR markers from Mršić et al. 2012, divided into five Croatian regional populations (North, Central, West, East and South Croatia) with 220 samples each. Compared to the scientific study, there were 2 less R1a samples in the population of North Croatia. The frequency of R1a in North Croatia was the highest (28.18%), followed by Central Croatia (23.63%), West Croatia (20%), East Croatia (19.1%) and South Croatia (18.63%), with general Croatian frequency of 21.91% (241/1100).

It is confirmed that the majority of Croatian R1a's frequency belonges to clade R-Z280/M558 (14.54-16.18%), followed by other two main clades R-M458 (5.45-6.0%) and R-Z93 (0.27-1.45%). The percentage share of clades on R1a level are R-Z280/M558 (66.3-73.8%), R-M458 (24.8-27.3%) and R-Z93 (1.2-6.6%).

The highest frequency R-Z280/M558 was in North Croatia (18.18-20.45%), followed by Central Croatia (15.45-16.81%), West and South Croatia have the same (roughly between 14-15%) while lowest in East Croatia (10.45-12.27%). The highest percentage ratio of R-Z280/M558 has been found in regional populations of South (76.2-83.3%) and West Croatia (70.4-77.2%) while lowest in East Croatia (56.1-65.8%).

Mršić et al. 2012

The raw uncorrected R-Z280/M558 subclade list with number of haplotypes is:

Croatian regional populations subclades (uncorrected list) - Mršić et al. 2012 on 17 Y-STR

Four haplotypes (one in West and three in South Croatia, with five total number of samples) possibly belonged to R-CTS8816 > S18681 subclade, but one of them, like in case of Slovenia, was rather predicted to be a R-Z93 subclade or R-CTS8816 > Y1392/Y2902 in general as close second and because of rarity of such subclade prediction and table simplicity they were counted as R-CTS8816 > Y1392/Y2902 (!). After re-checking all haplotypes, in the corrected list are also removed rare R-Z280/M558 subclades R-Y10805 (1-2), R-YP5000 (2), R-YP1019 (4), R-YP6228 (1) and R-Z1907 (1) replaced with close second listed subclades, making the list of R-Z280/M558 subclades from the most to less frequent and distributed on level of Croatia roughly as, R-Y1392/Y2902 (42-51), R-Y2613 (38-43), R-YP343 (22), R-L1280 (19), R-Y4459 (11-12), R-YP953 (8-9), R-YP270 (5), R-YP582 (4-5), R-YP4278 (4), R-YP1034 (3), R-L366 (2-3) and R-FT14137/Y167503 (2). The regional population with highest variance was Central and South Croatia, others are basically the same in variance with West Croatia seemingly having less rare subclades. Generally R-Y1392/Y2902 is the most frequent subclade in Croatia, but it shares same percentage with R-Y2613 in North Croatia, with R-L1280 in Central Croatia, and is lowest in East Croatia, while R-Y2613 is highest in the same region. R-YP343 is mostly present in North and West Croatia, evenly in other regions. R-L1280 is also well present in East and South Croatia, lower in West and absent in North Croatia. R-YP953 is highest in West Croatia, evenly in other regions. R-Y4459 is evenly present in all regions aside none sample in South Croatia. Other subclades are more rare, with R-YP4278 absent in North and East Croatia, R-L366 absent in Central, West and South Croatia, R-YP270 absent in Central, West and East Croatia, R-YP582 absent in West, East and maybe South Croatia, R-YP1034 in North and West Croatia, and R-FT14137/Y167503 in North, Central and East Croatia.

The highest percentage ratio of R-M458 have been found in regional populations of East (34.1-39.0%), Central (28.8-30.7%) and North Croatia (25.8-29.0%) with similar frequencies ranging between 6-8%, while lowest in West and South Croatia (16.6-19.0%) with a frequency of roughly 3%. The found subclades frequency & percentage is different than in previous population of Zagreb+Croatia as the majority is R-L1029 (c. 60%) not R-L260 (c. 40%). Their ratio is 50-50% in North, West and East Croatia, and 25-75% in favor of R-L1029 in Central and South, with only 1 haplotype of R-A11460 in Central Croatia.

R-Z93 is everywhere in very low or almost absent frequencies (0-2.27%), with highest possible frequencies in West (0.91-2.27%) and North Croatia (0.45-1.81%).

Croatian regional populations frequency (corrected list) - Mršić et al. 2012 on 17 Y-STR

Third study with Croatian samples is Šarac et al. 2016 with 720 Y-SNP samples divided into of eight islands (N=384; Cres, Dugi otok, Lastovo, Mljet, Pag, Pašman, Ugljan, Vis) and mainland (N=336) and subset of 129 samples designated as three haplogroups including "R1a1a1b1a*-M558 (N=48)" typed for 17 short tandem repeats (Y-STRs). The general cumulative frequencies (Y-SNP) for Croatia confirm previous frequencies & percentage of R-Z280/M558 (19.30%), R-M458 (6.80%) and R-Z93 (1.38%), as well as "regional" of islands R-Z280/M558 (22.91%), R-M458 (9.63%) and R-Z93 (1.04%) and mainland R-Z280/M558 (15.17%), R-M458 (3.57%) and R-Z93 (1.78%). Compared to previous five regions, supposed islands "regional population" would have highest R1a and R-Z280/M558 and R-M458 frequencies in Croatia (partly due to inflated disproportionate number of samples from norhtern island of Cres), but the percentage ratio of clades is the same as in other regional and national Croatian populations (68.21% - 28.68% - 3.10%). 

There's some difference in the frequency of R1a between northernmost and southernmost islands (for example as previously reported for islands of Krk in the north and Brač, Hvar and Korčula in the South based on Y-SNP from Underhill et al. 2009). Such frequencies are also result of founder effect due to isolation and small population, especially Cres with 56.6% R1a (specifically R-M558 29.3% and high R-M458 27.3%) is an exception in Croatia and among the Croatian islands as even near Krk with 36.5% R1a has mostly R-M558 24.3% and less R-M458 12.2% respectively. Those additional four islands populations together make a second representative insular "regional population" (N=348), but in the study only R-M458 is differentiated so was joined R-Z280/M558 with R-Z282, having a lower R-Z280/M558+Z282 (14.94%) and R-M458 (4.02%). When all the twelve islands populations are calculated together, making the most representative islands "regional population" so far (N=732), the frequency of R1a is almost the same as the mainland frequency (26.63%), R-Z280/M558+Z282 is also the same (19.67%), and R-M458 as well (6.96%). Overall without any significant difference in clades frequency compared to the mainland population(s). Interestingly, and more accurately, when the R1a frequencies are calibrated according to the demographic size of the islands, the insular population with 8 islands has 27.82% R1a, the insular population with 12 islands has 26.30% R1a, the insular population with 10 Dalmatian islands has 21.59%, and the insular population with 2 Kvarner islands has 41.06%.

Regarding the Y-STR haplotypes there's a complete chronological overlap with R-Z280/M558 haplotypes of "Croatian islands" (40) and "mainland" (15) from slightly older study Underhill et al. 2014 (known to have erroneous frequency data for Croatia on 31/108 samples in Table S4 in the supplementary Excel file, which is correctly shown in Underhill et al. 2009), which study also included 14 R-M458 haplotypes without designated location (possibly islands) and no reference for all of them. It seems the older study included preliminary data designated for Šarac et al. 2016 (33) hence later in comparative matches analysis will be used initial 40 haplotypes plus 2 unique unmatched haplotypes (of R-Y4459 and R-YP4278) from Šarac et al. 2016 with confirmed island location, but won't RM458 haplotypes because their location is uncertain. Firstly, as will be seen now, the predicted subclades don't differ between 40 and 33 counted haplotypes.

In the R-Z280/M558 haplotypes analysis is seen that the majority of frequency & percentage is made of top three subclades R-Y1392/Y2902, R-Y2613 and R-YP343, with R-Y2613 being most frequent island's subclade (32-36%), but in this observed haplotypes was total absence of R-L1280 in both islands and mainland population, although the former was on representative (33-40) the latter was on a relatively small number of haplotypes (15) and considering previous regional and national populations it is certainly well present in Croatia, but compared to previous five regions R-L1280 can be said for now it was absent in the islands and North Croatian population, dialectologically it would be location extremities of Chakavian and Kajkavian compared to Shtokavian dialect group (as R-L1280 was well present in Kajkavian speaking Central Croatia). Instead had higher percentage presence of the subclade R-FT14137/Y167503 (6-10%), R-YP4278 (5-9%), R-YP953 (5-6%), R-Y4459 and R-YP582 (2-3%).

As for the R-M458, the subclade R-L1029 (57%) was again more frequent than R-L260 (43%), while in R-L260 roughly 33% share was made of subclade R-YP1337.

Croatian eight islands clades (Y-SNP) and (sub)clades (on 17 Y-STR) - Underhill & Šarac et al. 2014-2016

Croatian twelve islands main clades (Y-SNP) - Underhill & Šarac et al. 2009-2016

There were 2 duplicate haplotypes on intrapopulation level of Croatia (2/26/125) and additionally 2 duplicates on interpopulation level of Zagreb & Croatia (4/57/239), for a total of 53/57 unique haplotypes, an evidence of high diversity. Among the regional populations of Croatia lowest number was in Central (1), followed by North and West (2), South (3) and East (4), while Croatian islands (6). Similar numbers were found for Slovenia (3), Ljubljana+Slovenia (7), Bosnia and Herzegovina (2), Serbia (3) and Western Balkans Serbs (4). The duplicate frequency compared to the number of R1a (in case of Croatian islands only R-Z280/M558) samples of observed population, was highest in Serbs (9.1%) and Serbia (8.8%), followed by Ljubljana+Slovenia (7.7%), Zagreb+Croatia (7%), Bosnia and Herzegovina (5.1%) and least in Slovenia (4.6%), while among Croatian regional populations expectedly was highest in the islands (14.3%) followed by East (9.7%), South (7.1%), West (4.5%), North (3.2%) and Central Croatia (1.9%). The cumulative population of Croatia on 241/1100 samples had only 13 duplicates for very low duplicates frequency of 5.3% and 1.1% confirming very high diversity of R1a haplotypes in Croatia.

The duplicate haplotypes in Croatian populations from Mršić et al. 2012 were on subclades R-Y1392/Y2902 (5), R-Y2613 (3), R-Y4459 (2), R-YP953 (1), R-Y5647 (1) and R-L1029 (1), from Purps et al. 2014 were on R-Y1392/Y2902 (1), R-Y2613 (1), R-Y4459 (1) and R-L260 (1), from Underhill et al. 2014 & Šarac et al. 2016 were on R-Y1392/Y2902 (3), R-Y2613 (2) and R-FT14137/Y167503 (1).

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian duplicate haplotypes on 17 Y-STR

As said, there were 2 interpopulation exact matches between Zagreb and Croatia 17 marker haplotypes from Purps et al. 2014, but on both 23 and 17 Y-STR markers were rightly predicted same clade, subclade and for one even sub-subclade (on R-Y1392/Y2902 and R-L260). To find viability and usefulness of 1-Step Neighbor on 16 markers were also checked those intrapopulation and interpopulation mathces. It was found that 11 out of 11 matches were on the same predicted clade and subclade (100%), and 7 out of 11 matches were on the same predicted sub-subclade (64%) making such information possible for consideration alongside exact matches. Due to low frequencies of duplicate R1a haplotypes in all observed populations, was not made matches analysis on unique haplotypes.

According to exact and 1-Step Neighbor matches number, but also should be taken into account population's sample size and number of R1a haplotypes in calculation (!), Croatian populations cluster together, Slovenian are very close to them, Bosnian and Herzegovinian would be close or between them and Serbian populations, while Serbian populations, especially of Serbia, somewhere intermediately distanced between them and other non-observed population (Macedonian-Bulgarian and Romanian).

Population of Zagreb+Croatia was expected to be geographically closest to regionally North and Central Croatia, although it had zero exact matches with Slovenian populations (and B&H) it had high number of neighboring matches with them and more with B&H than Serbian populations. North Croatia had most neighboring matches with Slovenian populations but high number with all populations except of B&H and Serbia. Central Croatia barely had any exact matches with Slovenian and had low matches count with Serbian populations. West Croatia had most exact matches with Slovenian populations, and was closest with neighboring matches to North and South Croatia. East Croatia was regional population with lowest matches number with population of Serbia, evenly close to other Croatian populations and Slovenia. South Croatia was evenly close to Croatian thou closest was East Croatian population, followed by Slovenian, Serbian and B&H populations, a Croatian region with most neighboring matches with population of Serbia. Croatian islands with only R-Z280/M558 haplotypes were closest to Slovenian and near West and South Croatian populations (most exact matches with North and South Croatia), followed by distant North and Central Croatia and Zagreb+Croatia, while lowest number of matches were with population of B&H, Serbia and Western Balkans Serbs. Bosnian and Herzegovinian population had most exact matches with North Croatia and Serbia, but lowest number of neighboring matches was with Serbia.

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian haplotype matches on 17 Y-STR

To get a broader perspective and context on the subclades distribution, frequencies and matches of Southwestern Slavs were then analyzed three populations which could be said are representative of the Southeastern Slavic genetic background, solely Bulgarian (R1a 55/247) from Karachanak et al. 2013 (17 Y-STR), second a mixed Bulgarian-Romanian (15+32/241) from Martinez-Cruz et al. 2015 (17 Y-STR), and third of ethnic Macedonians from North Macedonia (14+19/204) from Purps et al. 2014 and Jankova et al. 2019 (23-27 Y-STR).

Beforehand it should be noted that until now the observed population of Serbia has lower number of R1a haplotypes, sometimes almost double than some Croatian and all Slovenian populations, partly because was intended to have populations with similar sample size. This was mostly fixed with having second Serbian population representative of the ethnic Serbs in the Western Balkan countries of Serbia, Montenegro, Bosnia and Herzegovina, and Croatia. Neverthless results are peculiarly conclusive. As the population of Serbia is bigger than of the other analyzed nations and to have a more representative comparison with almost equal number of R1a haplotypes, for this match comparison were added another 26 haplotypes from Mirabal et al. 2010 to make two populations of Serbia, standard with lower (34) and higher but more representative (60) number of R1a haplotypes. In the new population the frequency of duplicate haplotypes grew to 13.3% and most probably would even more with an increase in the number of samples as such definitely making Serbian population the population with the least diversity of haplotypes among Southwestern Slavs, but not necessarily subclades as it only indicates a general population's founder effect. It confirmed previous remarks about matches, and seemingly the frequency of R-Z280/M558's is almost equally distributed between seven different subclades.

Serbian extended R1a haplotypes subclades and matches on 21 & 17 Y-STR

The observed "Southeastern Slavic" populations had higher R1a frequency (22-19-16%) than both Serbian populations as well as new Serbian population. Bulgarian population was overall fairly diverse, possibly being the most diverse of all observed nations, while Bulgarian-Romanian had highest frequency of duplicate haplotypes (19%), but due to haplogroup variance between Romanian regions in reality could also have high diversity. North Macedonian on lower number of haplotypes seems an exceptional case in the Balkans. Regarding clades, the R-M458 makes slight majority in Bulgarian (52%) unlike Southwestern Slavs while the R-Z280/M558 in Bulgarian-Romanian (65%) alike Southwestern Slavs. North Macedonian also has higher R-M458, and there exist local cases with very high general frequencies of R-M458 (>56%, Zupan et al. 2020). In all three populations subclade R-L1029 made the majority of R-M458 (75-70-80%), in Bulgarian and North Macedonian population R-A11460 was more frequent than R-L260 (13 > 10% / 20 > 0%), like in Serbian populations. Roughly the first five subclades of R-Z280/M558 make the majority of the same clade, with the exception of North Macedonia, but percentages of ratio are a bit different than among Southwestern Slavs, as R-Y1392/Y2902 would be in all populations around 15%, but R-Y2613 varies between 25-13-7% and R-L1280(>Y5647 and one FGC19283) between 12.5-29-0% respectively, R-YP343 is absent or low in North Macedonian and Bulgarian (0-5%) but high in Bulgarian-Romanian (16%) and R-Y4459 is high in North Macedonian and Bulgarian (14-16%) but low in Bulgarian-Romanian (3%). In all R-YP953 is almost absent or low (0-3-7%), and all other subclades are individually present in traces (3-5-7%), with the exception of rare R-YP1034 reaching 30% in North Macedonia. This could be trace of some local (East) Slavic tribal founder effect or prediction mistook it with some other subclade (presumably R-Y1392/Y2902 or other). Seemingly there's a good overlap with Serbian population (minus high R-YP953), as of Croatian regional possibly East Croatia (minus high R-Y2613), while partly with Bosnian and Herzegovinian (minus no R-Y1392/Y2902), and general Croatian-Slovenian (minus high R-Y1392/Y2902).

Bulgarian, Bulgarian-Romanian, North Macedonian R1a subclades and matches on 23-17 Y-STR

They expectedly had most matches, especially 1-Step Neighbor matches, between themselves (3/21-0/24-4/25) but also Serbian population (2/24-2/25-6/22). North Macedonian had most matches with Serbian (6) and Bulgarian (4) while Bulgarian population had most exact matches also with Bulgarian-Romanian and Western Balkans Serbs (3), followed by Serbian (2) and cumulative Ljubljana+Slovenia (2), but the latter had almost double less 1-Step Neighbor matches (11<16-24) although having 30-46 more haplotypes than Serbian populations nonetheless. Although most exact matches were found between Bulgarian-Romanian and East Croatia (5), Zagreb+Croatia (4) and West Croatia (3), all Croatian populations had much lower (1-10, average 7) number of 1-Step Neighbor matches than Serbian populations (16-25), implying that the exact matches are anecdotal and irrelevant to the general context. Actually, to all three Bulgarian, Bulgarian-Romanian and North Macedonian populations most distant with a very low number of exact and 1-Step Neighbor matches were populations of Croatian islands (0/5-0/1-0/1), Slovenia (1/2-0/4-0/5), Zagreb+Croatia (0/6-4/3-0/5), South Croatia (1/7-1/6-0/14) and so on. In conclusion could be said that among observed national populations, Serbian's genetic background is definitely or heavily divided between Southwestern and Southeastern Slavic ancestry or is majorly of Southeastern Slavic origin, having sub-subclades (e.g. R-YP417>YP418) less common among Southwestern but much more common among Southeastern Slavs and vice versa. This is a confirmation of the complex processes of changes in ethno-political borders, identities and population replacement from the 10th and 12th centuries of medieval and modern Serbia.

Quote of De Administrando Imperio and a map of the late 9th century with approximate borders of early medieval Principality of Serbia as well as projected borders (yellow) of modern day Serbia

2.2 R1a subclades frequency and variance in some East and West Slavic populations

Ukrainian, Polish, Northeast Hungarian, Slovakian, Czech, Southeast German and Sorbian subclades

Then were analzyed R1a subclades and frequencies in some East and West Slavic populations, mostly on 23 and less 17 or 15 Y-STR, specifically, the city of Lviv and Western-Central Ukraine, the city of Kraków and Wrocław in Poland, Northeast Hungary, Slovakia, Czechia, the city of Leipzig and Sorbs in Lusatia both in Saxony in Germany (for scientific references and number of samples see in continuation the 2.3 chapter; in addition in the 2.3 chapter are mentioned other frequencies from Underhill et al. 2009/2014 and Kushniarevich et al. 2015).

The highest R1a frequency was among Sorbs in Lusatia (65%), followed by Wrocław (50%) and Kraków (49%), Slovakia (46%), Lviv (43.5%), Czechia and Northeast Hungary (32%), and lowest in Leipzig (25%). In some populations (Northeast Hungary) the lowering of the frequency has parallel rise of the I2-CTS10228 frequency, but in some there's no such effect (Leipzig, Czechia). The highest frequency of clade R-Z280/M558 was in Lviv (27%), Wrocław (22-25%) and Slovakia (23%), while lowest in Sobrs (7%), Leipzig (7-8%) and Czechia (11-13%). The highest frequency of the clade R-M458 was in Sorbs (57%), Kraków (32.8%) and Wrocław (24%), while lowest in Lviv and Leipzig (13%). As the R-Z93 and R-other (mainly Western-Northeastern European non-Slavic clades) have minimal frequencies (0-2.6%) won't be specially analyzed besides said that R-Z93 has highest frequency in Lviv (2.6%) and possibly Wrocław (1-4%), while R-other in Leipzig (1.6-2.4%) with tendency for West Slavs.

However, the clades frequencies are better perceived and understood when is compared their percentage ratio of R1a. The highest percentage of R-Z280/M558 (CTS1211+Z92) was in Western-Central Ukraine and Lviv (65-66%) and steadily falling down toward the West, followed by Slovakia (50%), Wrocław (44-50%), Northeast Hungary (43%), Czechia (36-42%), Kraków (33%), Leipzig (29-33%), Sorbs (11.5%). The highest percentage of R-M458 was in Sorbs (87.5%), followed by Kraków (66%), Leipzig, Czechia and Northast Hungary (52-53%), Wrocław and Slovakia (48%), and lowest in Western-Central Ukraine and Lviv (33-34%). The only exception disturbing linear direction of inclination is Kraków but it is expected to have various degrees of variance in Poland.

The results confirm old conclusions by Underhill et al. 2014 and else that although R-Z280/M558 and R-M458 subclades have similar distribution and frequenices in Eastern and Central Europe, the former has higher frequencies in Eastern Europe among East Slavs (also Volga-Uralic populations), the latter has higher frequencies in Eastern-Central Europe among West Slavs. However, neverthless the simplified identification of R-Z280/M558 as East Slavic and R-M458 as West Slavic on their subclades and sub-subclades level exist further division. R-Z280 is mainly represented by R-CTS1211/M558 which could be considered as Proto-Slavic (R-YP343, R-YP1019, R-Y10805, R-YP1034 and big subclade R-Y35 with many sub-subclades) and less R-Z92 which could be considered as Balto-Slavic (R-Y4459, R-Z685), while R-M458 is mainly represented by more West Slavic R-L260 (R-YP1337 which is more common in East Slavs and R-YP256 which is more common in West Slavs) and more East Slavic R-CTS11962 (R-L1029 and R-YP515 which have sub-subclades more common in West or East Slavs), while small subclade R-A11460 seems mainly Polish-Ukrainian.

Regarding the subclades of R-Z280/M558, the R-Y1392/Y2902's share percentage was highest in Western-Central Ukraine (33-34%) and Slovakia (30%) but as it was falling down it was being steadily replaced by sister's subclade R-Y3301>S18681 which was rising up, with the parallel rise of R-M458, in Czechia (6-7%), Kraków (9%), Leipzig (19-21%) and Sorbs (77%). In last two populations R-Y3301>S18681 made or most common subclade or majority of R-Z280/M558 share ratio. R-Y2613 number of haplotypes and share percentage was also more common in the East-Central (4-7/11-18%; Northeast Hungary, Slovakia, Ukraine, Kraków) than the West (1-2/6-11%; Wrocław, Czechia, Leipzig, Sorbs). R-YP343's number of haplotypes and share was high in Northeast Hungary (11/28%), Slovakia (10/16%), Lviv (9/21%) and Czechia (3/18-21%) and lowest in Sorbs (0%), Wrocław (1-2/4.5-8%) and Leipzig (2/7-8%). R-Y3301>L1280 was present almost everywhere (excluding Wrocław) with similar percentages, but predicted sub-subclade R-Y5647 was present mostly in Ukraine and Saxony while elsewhere almost only sub-subclades FGC19283 and FGC11555 not common in the Balkans. R-YP953's number of haplotypes and share was mainly in Lviv and Northeast Hungary (3/7%) and Kraków (2/9%). R-Y4459's number and share was expectedly highest in Western-Central Ukraine (6/22-23%), but also Slovakia (7/11%) followed by cities of Lviv, Kraków and Wrocław (3-4/9-13%), while almost absent or absent in Czechia and Saxony. R-YP234's subclades YP238 and YP295>YP335 had similar percentages, absent or not, everywhere, most common both being in Leipzig (3/11-13%), while R-YP335 in Lviv (4/9.5%) and YP238 in Wrocław (3/12-13%). R-YP270 was present almost everywhere with highest number of haplotypes and share in Lviv (5/12%), Northeast Hungary (4/10%). R-YP4278 was present in Northeast Hungary (3/7%), Slovakia (1/1.5%) and Leipzig (1/4%). Other subclades are found sporadically without much connection and interest for the South Slavs, but are ancestrally related to the East Slavs.

Regarding the subclades of R-M458, the R-L260 had highest share in Wrocław (75%) and Sorbs (68.5%), followed near by Kraków, Czechia, Northeast Hungary and Slovakia (63-66%), and lowest in Western-Central Ukraine and Lviv (35-43%) and interestingly Leipzig (34%) where in those populations on the contrary was higher R-L1029 (52-64%). As for individual sub-subclades, of particular South Slavic interest is R-L260>R-YP1337, although sometimes confused with rare sub-subclade R-Y4135 of different branch, is highest in Western-Central Ukraine and Lviv (20-33%) as well as Northeast Hungary (28%), while lowest in Sorbs (6%).

Haplogroup R-M558 and R-M458 subclades distribution from "Haplogroup R1a" by Vayda (2018)

Proto-Slavs were related to the Kyiv culture hence placing the large Slavic subclades in a region of Southern Belarus and Northern Ukraine. Some of them subsequently expanded toward North-Western Ukraine and the Carpathian region, being related to the Prague-Korchak culture of the Sclaveni while others to the Prague-Penkovka culture of the Antes. During the migration period in the territory of Eastern Balkans was also formed a mixed Ipotești–Cândești culture. Probably both the Sclaveni and Antes were predominantly R-Z280/M558 and those moving to Central Europe additionally assimilated R-M458 (some subclades were present in Central Europe already since the Late Bronze Age).

The region of Southeastern Poland and Western Ukraine was a middle & central, transitional zone between East and West Slavs but more related to the East Slavs. Through the Eastern Carpathian passes (like Veretsky and Dukla Pass) were connected Polish and Ukrainian Subcarpathian regions with Eastern Slovakia and Northeastern Hungary, connecting them with the river Tisza in the Carpathian Basin. However, the Tatra Mountains in the Western Carpathians can also be passed, connecting Southern Poland with Central and Western Slovakia. To the west between Western Beskids and Sudetes was Moravian Gate for easier entrance to the Bohemian Massif, Vienna Basin as well as Pannonian Basin from the west. To the far East of Eastern Carpathians was third main route of migration, going alongside Eastern Carpathians into the Romanian Plain.

A map based on linguistic and archaeological data. It is also confirmed by historiographical, anthropological, and genetic data. For a high-quality map see Scribble Maps

R-YP343>YP340>YP371 and P278 are common in both East and West Slavs, migrating through all directions. R-L1280 is mostly East but also West Slavic, probably also migrating through all directions, but its subclade R-Y5647 only from Eastern Carpathians. R-S24902 can be found in both Poland and Belarus, migrating through Eastern East Carpathians. R-Y1392/Y2902, also named as "Carpathian-Russian" or "Volgo-Carpathian" because of high concentration on the border of West-East Carpathians and in European Russia, with its subclade R-FGC10360/Y3226 (77-87% share of R-Y1392/Y2902 in Northeast Hungary and Slovakia) mostly migrated from between Southeastern Poland and Western Ukraine in the Eastern Carpathians through Pannonia. R-Y2613 is common in both East and West Slavs (an archaeogenetic 13th century sample from Yaroslav, European Russia, belonged to R-Y2613, Mustafin et al. 2022, pg. 111), but it and its subclade R-Y2608 named as "Carpathian-Dalmatian" mostly migrated between Southeastern Poland and Western Ukraine from Eastern Carpathians through Pannonia, but also in all directions. R-L260 would be more West Slavic (especially in the case of Poland) and partly East Slavic (particularly in West Ukraine and Russia), migrated through East and West Carpathians-Pannonia and Moravian Gate while R-L1029 would be both West and East Slavic, migrating more through East Carpathians-Pannonia and Eastern East Carpathians and less through Moravian Gate.

A bit outdated map of R-Y1392/Y2902 by FTDNA's R1a project (2011)

A bit outdated map of R-Y2613 by FTDNA's R1a project (2011)

2.3 Matches on 17 markers with East and West Slavs (reinforced by 23 markers reliability)

To confirm assertions on frequency and distribution of clades and subclades among East and West Slavs as well their putative migrations, also related to South Slavs, were compared Southwestern Slavic haplotypes with 17 Y-STR markers of West and East Slavic populations, showing both exact and 1-Step Neighbor matches number list (the mentioned number of "different" and "unique" haplotypes referes to haplotypes of Southwestern Slavic populations and refers to difference between number of matched haplotypes and unique haplotypes). It will be also listed exact matches on predicted sub-subclades. 

Southeastern European populations with Southeastern Slavic ethnolinguistic identity and genetic background (Bulgaria, North Macedonia and Romania) won't be analyzed because their Slavic ancestry is historically and archaeologically more straightforward and established to be almost exclusively from territories of East Slavs (early medieval Prague-Penkovka and mixed Ipotești–Cândești culture).

- European Russia:

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian matches with Russian on 17 Y-STR

The analyzed population of Russia was from Roewer et al. 2008 (17 Y-STR) and were chosen six southernmost administrative oblasts with 259 out of 545 samples from European part of Russia. They were personally divided into two populations, "western" (R1a 63/128) including Smolenskaja (24/43), Brianskaja (20/43) and Orlovskaja (19/42) and "eastern" (R1a 69/131) including Ryazanskaja (18/36), Lipezkaja (24/47) and Tambovskaja (27/48). According to Underhill et al. 2009/2014 and Kushniarevich et al. 2015, Russians have often R1a over 50-60% but R-Z280/M558 is a predominant clade.

Zagreb+Croatia had 6 exact matches on 5 different and 4 unique haplotypes of R-Y1392/Y2902>Y2910 (x2 same haplotype), R-Y2613, R-L260>Y4135, R-L260>YP1337 and R-L1029>YP416. The number of 1-Step Neighbors was 24.

North Croatia had 7 exact matches on 4 unique haplotypes of R-L1029>YP4647 or BY30715 (x4), R-Y2613, R-YP953, and R-L260>YP1337 or Y4135; Central Croatia had 1 exact match on R-L1029>YP6048; West Croatia had 3 exact matches on 3 unique haplotypes of R-YP953, R-L1029>YP6048, and R-L260>YP1337 or Y4135; East Croatia had 2 exact matches on 2 unique haplotypes of R-Y2613 and R-L1029>YP6048; South Croatia had 3 exact matches 3 different and 2 unique haplotypes of R-Y2613 (x2) and R-L1029>YP6048. The number of 1-Step Neighbors was 32-22-32-32-28 with an average of 29 matches.

Croatian islands only with R-Z280/M558 had 11 exact matches on 9 different but 5 unique haplotypes of R-Y1392/Y2902 (x4), R-Y4459>Y5570 (x4), R-Y2613 (x2), and R-YP4278. The number of 1-Step Neighbors was 31.

Slovenia didn't have any exact matches but cumulative population with Ljubljana had 3 exact matches on 3 unique haplotypes from Ljubljana of R-Y2613 (x2), R-L1029>YP6048. The number of 1-Step Neighbors was 35 and 75. Although the Ljubljana+Slovenia population it has higher total number of R1a haplotypes than individual Croatian populations it doesn't have same or higher number of exact matches than them, Slovenia doesn't have much more 1-Step Neighbor matches, while Ljubljana+Slovenia has same or similar 1-Step Neighbor matches (75) as two together Croatian populations with similar number of R1a haplotypes - showing that population of Croatia probably has more "Russian-related" (East Slavic) ancestry than population of Slovenia.

Bosnia and Herzegovina had 8 exact matches on 4 unique haplotypes of R-L1029>YP417 (x4), R-YP953 (x2), R-Y2613 and R-YP582. The number of 1-Step Neighbors was 30.

Serbia had 6 exact matches on 3 unique haplotypes of R-L1029>BY30715 (x4), R-L1029>YP6048 and R-YP953. The number of 1-Step Neighbors was 21. The population of Western Balkans Serbs had also 6 exact matches but on 2 unique haplotypes of R-L1029>Y34164 (x4) and R-Y1392/Y2902>Y4380 (x2) however the number of 1-Step Neighbors was 42.

- Belarus:

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian matches with Belarusian on 17 Y-STR

The analyzed population of Belarus was from Rebala et al. 2011 (20 Y-STR) divided into four historical-ethnographical regions, northern (the Western Dvina river region, 85), northwestern (the Neman river region, 87), eastern (the Dnieper river region, 57) and southern (Polesia, 99). They were personally divided into two populations, "north-northwestern" (172) and "eastern-southern" (156). Another separate population was from Ballantyne et al. 2014 (17 Y-STR) but it is on a general population (100). The haplotypes weren't analyzed separately for the number of R1a samples, but according to the study of Kushniarevich et al. 2013, in specific regions on 100 samples can be expected more than 50 R1a samples and majority of them is R-Z280/M558 followed by R-M458 (in Belarus average frequency on 565 samples is 36.11% and 14.51%; similar frequency and proportion can be observed in Underhill et al. 2009/2014 and Kushniarevich et al. 2015, population of Belarus is another where R1a is often over 50-60%). From the matches count is slightly evident that "eastern-southern" population is closer to South Slavs than "northern-northwestern" which is probably also related to Balts.

Zagreb+Croatia had 2 exact matches on 2 different but 1 unique haplotypes of R-L260>Y4135 and/or R-L260>YP1337. The number of 1-Step Neighbors was 20+5.

North Croatia had 4 exact matches on 2 unique haplotypes of R-L1029>YP4647 or BY30715 (x3) and R-L260>YP1337 or Y4135; Central Croatia had zero exact matches; West Croatia had 1 exact match of R-L260>YP1337 or Y4135; East Croatia had 2 exact matches on 1 unique haplotype of R-L1029>FGC66331; South Croatia had zero exact matches. The number of 1-Step Neighbors was 26+5/10+1/14+4/26+8/16+4 with an average of 18+4 matches.

Croatian islands only with R-Z280/M558 had 10 exact matches on 5 different but 2 unique haplotypes of R-Y4459>Y5570 (x6) and R-Y1392/Y2902 (x4). The number of 1-Step Neighbors was 15+3.

Slovenia didn't have any exact matches but cumulative population with Ljubljana had 3 exact matches on 2 unique haplotypes from Ljubljana of R-L1029>FGC66331 (x2) and R-L260>YP1337. The number of 1-Step Neighbors was 15+2 and 32+6.

Bosnia and Herzegovina had 6 exact matches on 3 unique haplotypes of R-L1029>YP417 (x5) and R-YP582. The number of 1-Step Neighbors was 27+8.

Serbia had 5 exact matches on 2 unique haplotypes of R-L1029>BY30715 (x3), R-L1029>YP417 (x2). The number of 1-Step Neighbors was 18+8. The population of Western Balkans Serbs had 6 exact matches on 3 unique haplotypes of R-L1029>Y34164 (x3), R-L1029>YP417 (x2) and R-L1029>BY30715. The number of 1-Step Neighbors was 33+6.

- Ukraine:

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian matches with Ukrainian on 17 Y-STR

The analyzed population of Ukrainian city of Lviv was from Mielnik-Sikorska et al. 2013 (17 Y-STR) and number of R1a samples was 67 not 69 out of 154 as shown in the study. Unfortunately due to unavailable scientific data at the moment were additionally analyzed only 41 R1a haplotypes, from Underhill et al. 2014 (23) and Martinez-Cruz et al. 2015 (17 for exact, 18 for 1-Step Neighbors), both on 17 Y-STR and probably sampled from Western-Central Ukraine, for cumulatively below average representative population of Ukraine (108 R1a haplotypes in total). According to Underhill et al. 2009/2014 and Kushniarevich et al. 2015, population of Ukraine has on average 43-46% R1a but R-Z280/M558 is 29-32% and R-M458 13-14%, while Western Ukraine (incl. Ivano-Frankivsk and Lvov Oblast 27% and 16% and with Chernivtsi Oblast 24% and 19%; according to Ivano-Frankivsk Oblast data R-Z280/M558 is predominantly R-M558).

Zagreb+Croatia had 4 exact matches on 3 unique haplotypes of R-Y1392/Y2902>Y2910 (x2), R-YP343>YP371>YP372 or YP380 and R-L1029>YP416. The number of 1-Step Neighbors was 14+9.

North Croatia had 5 exact matches on 4 unique haplotypes of R-L1029>YP4647 or BY30715 (x2), R-Y2613, R-Y1392/Y2902>FGC10360, R-L260>YP414 or Y4135 or YP654; Central Croatia had 2 exact matches on 1 unique haplotype of R-L1029>YP6048; West Croatia had 3 exact matches on 2 unique haplotype of R-L1029>YP6048 (x2) and R-YP343>YP371>YP380; East Croatia had 3 exact matches on 2 unique haplotype of R-L1029>YP6048 (x2) and R-Y2613; South Croatia had 4 exact matches on 3 different but 2 unique haplotype of R-Y2613 and R-L1029>YP6048. The number of 1-Step Neighbors was 20+12/16+4/8+13/12+11/8+5 with an average of 12+9 matches.

Croatian islands only with R-Z280/M558 had no exact and 1-Step Neighbors matches with the population of Lviv, but with other Ukrainian samples had 3 exact matches on 3 different but 2 unique haplotypes of R-Y2613 (x2) and R-Y4459>Y5570, and the number of 1-Step Neighbors was 10.

Slovenia had 2 exact match on 2 unique haplotypes of R-L260>YP1337 and R-YP953. The cumulative population with Ljubljana had 6 exact matches on 5 unique haplotypes, 3 from Ljubljana, of R-L1029>YP6048 (x2), R-L260>YP1337 (x2) and R-Y2613. The number of 1-Step Neighbors was 4+20 and 11+31.

Bosnia and Herzegovina had 2 exact match of R-L1029>YP417 (x2). The number of 1-Step Neighbors was 10+3.

Serbia had 4 exact matches on 2 unique haplotypes of R-L1029>YP6048 (x2) and R-L1029>BY30715 (x2). The number of 1-Step Neighbors was 11+6. The population of Western Balkans Serbs had 5 exact matches on 3 unique haplotypes of R-Y1392/Y2902>Y4380 (x2), R-L1029>Y34164 (x2) and R-L1029>BY30715. The number of 1-Step Neighbors was 18+8.

- Poland:

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian matches with Polish on 17 Y-STR

The analyzed population of Poland was from Purps et al. 2014 on 23 Y-STR from which were chosen four sub-populations of Kraków (R1a 66/134), Central (58/102), Wrocław (51/100), Poznań (88/150). Poland's early medieval population certainly had a pivotal role in the history and migration of the West and South Slavs. However, when is made a comparison between contemporary Polish and Southwestern Slavic populations, for the intended and projected medieval context should not be ignored that the contemporary populations were shaped by historical, political and demographic events. Poland experienced a high level of natural population growth but also loss due to emigration in the 19th and 20th century, loss due to war in the 20th century and international-intranational migration and population transfers between neighboring states in the 20th century especially in specific regions. According to Underhill et al. 2009/2014 and Kushniarevich et al. 2015, in northwestern Pomeranian provinces is 55-60% R1a with 28-41% R-Z280/M558 and 22-27 R-M458; mid-northeastern Mazovia province is 60% R1a with 26% R-Z280/M558 and 34% R-M458; and southwestern Wrocław-Lower Silesian province is 56% R1a with 32% R-Z280/M558 and 23% R-M458.

Zagreb+Croatia with Kraków had 5 exact matches on 3 different but 2 unique haplotypes of R-L260>Y4135 or YP1337 (x2) and R-YP343>YP371 or YP3982; with Wrocław had 2 exact matches on 2 unique haplotypes of R-L260>YP654 or Y2905; with Central had 2 exact matches on 2 different but 1 unique haplotype of R-L260>Y4135 or YP1337 (x2); with Poznań had as well 2 exact matches on 2 different but 1 unique haplotype of R-L260>Y4135 or YP1337 (x2). The number of 1-Step Neighbors was 16+10+16+12.

North Croatia with Kraków had 4 exact matches on 3 unique haplotypes of R-L260>Y4135 or YP1337 (x2), R-L260>YP414 or Y4135, and R-YP343>YP371 or YP3982; with Wrocław had 2 exact matches on 2 unique haplotypes of R-YP343>YP371 and R-L260>YP654 or some other sub-subclade; with Central had 2 exact mathces on 2 unique haplotypes of R-L260>YP1337 or Y4135 and R-Y2613; with Poznań had 2 exact matches on 2 unique haplotypes of R-L260>YP1337 or Y4135 and R-L1029>YP4647 or BY30715. The number of 1-Step Neighbors was 14+9+22+13.

Central Croatia with Kraków had 1 exact match of R-Y1392/Y2902>FGC10360; with Wrocław had 1 exact match of R-Y2613; with Central had 2 exact matches on 2 different but 1 unique haplotype of R-Y2613; with Poznań had 2 exact mathces on 2 unique haplotypes of R-L260>YP5297 or other sub-subclade and R-L1029>YP1703. The number of 1-Step Neighbors was 11+8+5+12.

West Croatia with Kraków had 2 exact matches on 1 unique haplotype of R-L260>YP1337 or Y4135 (x2); with Wrocław had zero exact matches; with Central had 2 exact matches on 2 unique haplotypes of R-L260>YP1337 or Y4135 and R-YP953 or R-Y2613 or R-Y4459>FT2107; with Poznań had 3 exact mathces on 3 unique haplotypes of R-Y2613 or R-YP1019, R-YP953 and R-L260>YP1337 or Y4135. The number of 1-Step Neighbors was 8+5+18+14.

East Croatia with Kraków had 2 exact matches on 1 unique haplotype of R-L1029>FGC66331 or YP263; with Wrocław had zero exact matches; with Central had 1 exact match of R-Y2613; with Poznań had zero exact matches. The number of 1-Step Neighbors was 17+7+9+10.

South Croatia with Kraków had zero exact matches; with Wrocław also had zero exact matches; with Central had 2 exact matches on 2 different but 1 unique haplotype of R-Y2613; with Poznań also had zero exact matches. The number of 1-Step Neighbors was 6+6+8+8.

Croatian islands only with R-Z280/M558 with Kraków had 1 exact match of R-Y4459>Y5570; with Wrocław had zero exact matches; with Central had 2 exact matches on 2 unique haplotypes of R-Y2613; with Poznań had zero exact matches. The number of 1-Step Neighbors was 3+5+8+3.

Slovenia with Kraków had 1 exact match of R-L260>YP1337 or Y4135 or YP414 while Ljubljana additional 2 exact matches on 1 unique haplotype of R-L1029>FGC66331 or YP263; with Wrocław had 1 exact match of R-L260>YP1337 or Y4135 or YP414 while Ljubljana no additional matches; with Central had zero exact matches but Ljubljana had additional 1 exact match of R-Y2613; with Poznań both had zero exact matches. The number of 1-Step Neighbors was 8-18/6-11/12-23/8-18.

Bosnia and Herzegovina with Kraków had zero exact matches; with Wrocław had 1 exact match of R-L1029>BY30715 or YP263 or YP416; with Central had zero exact matches;  with Poznań had 2 exact matches on 2 unique haplotypes of R-L1029>YP416 or BY30715 or YP263 and R-L1029>YP4647 or BY30715 or YP417. The number of 1-Step Neighbors was 12+5+6+9.

Serbia (34) with Kraków had zero while Serbia extended (60) 1 exact match of R-L1029>YP416; with Wrocław both had zero exact matches; with Central had 1 exact match of R-YP953 while Serbia extended (60) had additional 1 exact match of R-L1029>YP263 or other sub-subclade; with Poznań had 2 exact matches on 2 unique haplotypes of R-YP953 and R-L1029>YP4647 or BY30715 or YP417 while Serbia extended (60) had additional 4 exact matches on 2 unique haplotypes for total of 6 exact matches on 3 unique haplotypes of R-L1029>YP619 (x3), R-L1029>YP4647 or BY30715 or YP417 (x2), and R-YP953. The number of 1-Step Neighbors was 9-20/6-10/9-16/13-22.

Western Balkans Serbs with Kraków had 2 exact matches on 1 unique haplotype of R-L1029>FGC66331 or YP263; with Wrocław had zero exact matches; with Central had 1 exact match of R-L1029>YP263 or other sub-subclade; with Poznań had 1 exact match of R-L1029>YP4647 or BY30715 or Y34164. The number of 1-Step Neighbors was 6+6+12+16.

In addition was made a partial analysis of two large sampled populations of Wrocław (463) and Warsaw (364) from Ballantyne et al. 2014 (17 Y-STR). Although exist significant difference in sample size between them as well as in area and population size between Lower Silesian and Masovian voivodeships they represent, according to Grochowalski et al. 2020, the frequency of R1a in Lower Silesia is roughly 53.9% while in Masovia is 61.18% and when used to calculate number of R1a samples in respective populations it is roughly 249 and 222 samples which is not too big a difference. Into account for comparison, for now, were taken only Zagreb+Croatia, Slovenia and Serbia extended with all clades and Croatian islands only with R-Z280/M558 clade. All of them had more or similar number of exact matches (6-5-10-9) with Wrocław than Warsaw (3-4-12-1), indicating Southwestern Slavic and particularly Croatian populations are more close to "Southern" than "Northern" Polish.

- Slovakia:

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian matches with Slovakian on 17 Y-STR

The analyzed population of Slovakia was from Underhill et al. 2014 (R1a 119/257) and Martinez-Cruz et al. 2015 (R1a 74/161) for a representative population. Both studies had 17 Y-STR markers. According to Underhill et al. 2009/2014 and Kushniarevich et al. 2015, the population of Slovakia has 46% R1a with 24.1% R-Z280/M558 and 21.4% R-M458 or 45% R1a with 29% R-Z280/M558 and 16% R-M458.

Zagreb+Croatia had 3 exact matches on 2 unique haplotypes of R-L260>YP654 or Y2905 (x2) and R-YP343>YP371>YP372 or YP380. The number of 1-Step Neighbors was 27+20.

North Croatia had 13 exact matches on 7 unique haplotypes of R-Y2613 (x5), R-L1029>YP4647 or BY30715 (x4), R-L1029>YP1703, R-YP343>YP371, R-YP270, R-Y1392/Y2902>FGC10360; Central Croatia had 3 exact matches on 2 unique haplotypes of R-YP343>YP371 (x2) and R-L260>YP5297 or some other sub-subclade; West Croatia had 5 exact matches on 5 unique haplotypes of R-Y1392/Y2902>FGC10360 (x2), R-YP343>YP371>YP380, R-YP953 and R-Y2613; East Croatia had 5 exact matches on 2 unique haplotypes of R-Y2613 (x4) and R-Y1392/Y2902>FGC10360; South Croatia had 7 exact matches on 3 different but 2 unique haplotypes of R-Y2613 (x6) and R-Y1392/Y2902>FGC10360. The number of 1-Step Neighbors was 37+29/15+11/22+25/30+13/29+18 with an average of 26+19 matches.

Croatian islands only with R-Z280/M558 had 10 exact matches on 4 unique haplotypes of R-Y2613 (x9), R-Y4459>Y5570. The number of 1-Step Neighbors was 16+26.

Slovenia had 5 exact matches on 4 unique haplotypes of R-Y1392/Y2902>FGC10360 (x2), R-Y2613, R-YP343>P278.2 and R-L260>YP1337. The cumulative population with Ljubljana had 10 exact matches on 6 unique haplotypes, 2 from Ljubljana of R-Y2613 (x5), R-Y1392/Y2902>FGC10360 (x2), R-L260>YP1337 (x2) and R-YP343>P278.2, the number of 1-Step Neighbors was 35+24 and 58+44. 

Bosnia and Herzegovina had 7 exact matches on 3 unique haplotypes of R-L1029>YP417 (x2), R-YP953 (x2) and R-Y2613. The number of 1-Step Neighbors was 19+9.

Serbia had 7 exact matches on 4 unique haplotypes of R-L1029>BY30715 (x4), R-YP953, R-Y1392/Y2902>FGC10360 and R-Y2613. The number of 1-Step Neighbors was 18+13. The population of Western Balkans Serbs had 7 exact matches on 3 unique haplotypes of R-L1029>Y34164 (x4), R-L1029>BY30715 (x2) and R-Y2613. The number of 1-Step Neighbors was 28+17.

- Northeast Hungary:

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian matches with NE Hungarian on 17 Y-STR

Before moving to next West Slavic peoples, will be analyzed neighboring population of Hungary and Hungarians (living in Slovakia) in Hungarian-Polish-Ukrainian-Slovakian contact zones. The analyzed populations are of the Bodrogköz villages (R1a 51/147) in Northeastern Hungary from Pamjav et al. 2017 and Hungarian-speaking Rétköz (R1a 42/106, Northeastern Hungary) and Váh valley (R1a 12/48, Western Slovakia) populations from Pamjav et al. 2022, both on 23 Y-STR markers. In the second study supplementary tables are found only 131 haplotypes (R1a 39+8) hence will be merged. In the majority is R-Z280/M558 or R-M458 clade in 60-40% share depending on the sampled population. These populations are relevant due to isolating areas in the proximity to Southern Poland and Western Ukraine, being on the early medieval route of the Slavic and other migrations to the Carpathian Basin as well as "ancient Hungarian Conquerors lived there and that many of their cemeteries have been excavated" (also Hungarian Conquerors have been said to intermarry and are friendly with the White Croats), everything essential to the understanding of the Slavic origin of Southwestern Slavs. According to Underhill et al. 2009/2014 and Kushniarevich et al. 2015, the population of Hungary has 20-28% R1a but predominance of R-Z280/M558 as only 4% is R-M458.

Zagreb+Croatia had 3 exact matches on 3 different and 2 unique haplotypes of R-L260>Y4135 or YP1337 (x2) and R-YP343>YP371. The number of 1-Step Neighbors was 15+8.

North Croatia had 4 exact matches on 3 unique haplotypes of R-L1029>YP4647 or BY30715 or YP417 (x2) and R-L260>YP1337 (x2); Central Croatia had 4 exact matches on 2 unique haplotypes of R-L1029>YP6048 (x3) and R-L260>YP5297 or some other sub-subclade; West Croatia had 9 exact matches on 5 unique haplotypes of R-Y2613 (x3), R-L1029>YP6048 (x3), R-L260>YP1337 or Y4135, R-Y1392/2902>FGC10360 and again R-Y1392/2902>FGC10360 or YP582; East Croatia had 6 exact matches on 2 unique haplotypes of R-Y2613 (x3) and R-L1029>YP6048 (x3); South Croatia had 4 exact matches on 2 unique haplotypes of R-L1029>YP6048 (x3) and R-Y1392/2902>FGC10360. The number of 1-Step Neighbors was 26+12/10+9/7+1/16+5/17+1 with an average of 15+5 matches.

Croatian islands only with R-Z280/M558 had no exact with both and no 1-Step Neighbors matches with the second population, but with the Bodrogköz samples had 12 1-S. N. on 9 different haplotypes.

Slovenia had 8 exact matches on 4 different but 2 haplotypes of R-Y2613 (x6 or x3), R-YP953 (x0 or x3), and R-Y1392/2902>FGC10360 (x2). The cumulative population with Ljubljana had 14 exact matches on 5 different but 3 unique haplotypes, 2 and 1 from Ljubljana of R-Y2613 (x9 or x6), R-YP953 (x0 or x3) and R-L1029>YP6048 (x3). The number of 1-Step Neighbors was 17+5 and 32+9.

Bosnia and Herzegovina had 3 exact matches on 2 unique haplotypes of R-L1029>YP417 or BY30715 (x2) and R-YP953. The number of 1-Step Neighbors was 13+4.

Serbia had 5 exact matches on 2 unique haplotypes of R-L1029>YP6048 (x3) and R-L1029>YP6048 or BY30715 or YP417 (x2). The number of 1-Step Neighbors was 14+7. Western Balkans Serbs had 2 exact matches on R-L1029>Y34164 or YP417 or some other sub-subclade (x2). The number of 1-Step Neighbors was 15+7.

- Carpathian Rusyns:

Carpathian Rusyns R1a subclades and matches on 23-17 Y-STR

The analyzed population of Rusyns was from "Carpatho-Rusyn FTDNA project" of those with 111 Y-STR (with necessary adjusting of Y-GATA-H4), but were chosen only those with confirmed origin location from Ukraine, Poland, Slovakia and Hungary, making in total 43 R1a samples, which is representative enough for a population numbering up to 1.7 million people. The results didn't change much. Most of them had done NGS/WGS test because of which was easier to re-check and confirm terminal SNP on 23 Y-STR and in all cases it was confirmed successfully (except one case of YP237 > FGC13681 subclade FT206829 which isn't available in Nevgen predictor, instead predicting sister subclades R-YP582 and R-YP953). There was only 1 duplicate haplotype on 17 Y-STR for high diversity (2.3%). The most common subclade was R-Y1392/2902>FGC10360/Y3226 (27%/71%) while of R-L260>YP1337 (36%).

Zagreb+Croatia had 1 exact match of R-Y1392/2902>FGC10360. The number of 1-Step Neighbors was 13.

North Croatia had 2 exact matches on 2 unique haplotypes of R-YP343>YP3982(>BY128749) and R-L1029>FGC66331 or BY30715 or some other sub-subclade; Central Croatia had 1 exact match of R-L260>YP5297 or some other sub-subclade; West Croatia had 2 exact matches on 2 unique haplotypes of R-Y1392/Y2902>FGC10360 and R-Y2613; East Croatia had 1 exact match of R-Y2613; South Croatia had 2 exact matches on 2 unique haplotypes of R-Y1392/Y2902>FGC10360 (x2). The number of 1-Step Neighbors was 17+5+5+10+11 with an average of 9 matches.

Croatian islands only with R-Z280/M558 did not have an exact match, but the number of 1-Step Neighbors was 7.

Slovenia had 4 exact matches on 2 unique haplotypes of R-Y1392/Y2902>FGC10360 (x2) and R-Y2613 (x2), while city of Ljubljana had additional 2 exact matches, for 3 unique haplotypes in total, of R-Y2613 and R-L260>YP1337(>FTB72996). The number of 1-Step Neighbors was 11 and 19.

Bosnia and Herzegovina had zero exact matches and the number of 1-Step Neighbors was 7.

Serbia (34) had 1 exact match of R-L1029>BY30715 or FGC66331 while Serbia extended (60) had 2 exact matches on 1 unique haplotype of R-L1029>BY30715 or FGC66331 (x2). The number of 1-Step Neighbors was 7 and 13. Western Balkans Serbs also had 1 exact match of R-L1029>BY30715 or FGC66331 or Y34164 and the number of 1-Step Neighbors was 8.

- Czechia:

Croatian, Slovenian, Bosnian and Herzegovinian, Serbian matches with Czech on 17 Y-STR

The analyzed population of Czechia was from Purps et al. 2014 (R1a 29/115) on 23 Y-STR, a same overlap with two more haplotypes on 117 samples from Ballantyne et al. 2014 (17 Y-STR), and additional 7 haplotypes from Underhill et al. 2014 (17 Y-STR) for a total of 38 unique haplotypes. In the majority is R-M458 clade with 52% ratio, but according to scientific studies it should be even higher; Underhill et al. 2009/2014 is 34% R1a of which 26% is R-M458 (76% ratio) or Kushniarevich et al. 2015 with similar results. The samples from Ewerlingová's dissertation 2014 weren't taken into account as it was research of same surnames because of which are repeated exact or very similar haplotypes and subclades. There were 31 unique haplotypes, most of them being R-M458 (65%; mainly R-L260) and minority R-Z280/M558 (mainly R-YP343). Although not shown in the table and text, the most matches with Croatian and other populations were predominantly only of R-L260.

Zagreb+Croatia had 3 exact matches on 3 different but 2 unique haplotypes of R-L260>Y4135 or YP1337 and R-L260>Y2905. The number of 1-Step Neighbors was 6.

North Croatia had 1 exact match of R-L260>Y4135 or YP1337; Central Croatia had zero exact matches; West Croatia had 2 exact matches on 2 unique haplotypes of R-L260>Y4135 or YP1337 and R-L1280>Y5647 or R-Y2613; East Croatia had 1 exact match of R-Y2613; South Croatia had zero exact matches and the number of 1-Step Neighbors was 8-5-3-9-7 with an average of 6 matches.

Croatian islands only with R-Z280/M558 had 1 exact match of R-YP343>YP371 or R-Y1392/Y2902 and the number of 1-Step Neighbors was 7.

Slovenia had 2 exact matches on 2 different but 1 unique haplotype of R-Y2613 (x2). The cumulative population with Ljubljana had 4 exact matches on 4 different but 2 unique haplotypes, 2 from Ljubljana of R-Y2613 (x3) and R-Y1392/Y2902>FGC10360. The number of 1-Step Neighbors was 8 and 14.

Bosnia and Herzegovina had zero exact matches and the number of 1-Step Neighbors was 3.

Serbia (34) had 1 exact match of R-M458>A11460 or R-YP953 while Serbia extended (60) had 2 exact matches on 2 different but 1 unique haplotype of R-M458>A11460 or R-YP953 (x2). Western Balkans Serbs had 2 exact matches of R-YP953 or R-M458>A11460 (x2) and the number of 1-Step Neighbors in both populations was 3 while in Serbian extended was 7.

- Saxony & Sorbs:

Southwestern Slavic populations matches with Saxonian and Sorbian on 17/15 Y-STR

The analyzed population of Saxony (Leipzig) was from Purps et al 2014 (R1a 77/303) on 23 Y-STR and Ballantyne et al. 2014 (43/215) on 17 Y-STR, which together had only 4 R1a interpopulation exact matches on the level of 17 Y-STR markers. The total frequency of R1a was 23.16% with 13.53% or roughly 53.2% ratio R-M458 (the dominant subclade was R-L1029 with ratio 63-34% versus R-L260). In addition separately was analyzed population of Upper Sorbian-speaking Sorbs in Lusatia from Rębała et al. 2012 (80/123) on 17/15 Y-STR, with 19 duplicate haplotypes (23.75%) and R1a frequency of 65% but with vast majority 56% or roughly 87.5% ratio was R-M458 (the dominant subclade was R-L260 with ratio 68-28% versus R-L1029). Considering the prevalence of R-M458 etc. the population of Saxony and Lusatia has significant difference to the near Lower Silesian province.

Zagreb+Croatia had with the both 1st and 2nd Leipzig population zero exact matches and the number of 1-Step Neighbors was 14+2.

North Croatia had 2 exact matches with 1st and 1 exact match with 2nd on 2 unique haplotypes of R-L1029>YP593 or BY30715 (x2) and R-L1029>YP1703; Central Croatia had 3 exact matches with 1st and 1 exact match with 2nd on 1 unique haplotype of R-L1029>YP6048, BY30715 or other sub-subclade; West Croatia also had same 3 exact matches with 1st and 1 exact match with 2nd on 1 unique haplotype of R-L1029>YP6048, BY30715 or other sub-subclade; East Croatia also partly had same 5 exact matches with 1st and 1 exact match with 2nd on 3 unique haplotypes of R-L1029>YP6048, BY30715 or other sub-subclade (x4), R-L1029>BY30715 and R-L1029>FGC66331; South Croatia once again also had same 3 exact matches with 1st and had 1 exact match with 2nd on 1 unique haplotype of R-L1029>YP6048, BY30715 or other sub-subclade (x4). The number of 1-Step Neighbors was 19+7/19+9/10+3/10+8/13+2 with an average of 14+6.

Croatian islands only with R-Z280/M558 had zero exact matches with 1st and had 1 exact match with 2nd of R-Y4459>Y5570 or R-YP295>YP335 and the number of 1-Step Neighbors was 1+1.

Slovenia had zero matches with both 1st and 2nd population of Leipzig. The cumulative population with Ljubljana had 5 exact matches on 2 unique haplotypes, both from Ljubljana of the same, but alike Croatian populations, was repeated R-L1029>YP6048, BY30715 or other sub-subclade (x4) and R-L1029>FGC66331. The number of 1-Step Neighbors was 3+5 and 12+12.

Bosnia and Herzegovina had 2 exact mathces with 1st and zero with 2nd population on 1 unique haplotype of R-L1029>YP593, BY30715 or YP417 (x2). The number of 1-Step Neighbors was 21+5.

Serbia (34), like previous populations, had 6 exact matches on 2 unique haplotypes of repeated R-L1029>YP6048, BY30715 or other sub-subclade (x4) and R-L1029>BY30715 or YP593 (x2). Serbia extended (60) had 13 exact matches on 5 different but 3 unique haplotypes of repeated repeated R-L1029>YP6048, BY30715 or other sub-subclade (x8), R-L1029>BY30715 or YP593 (x4) and R-L1029>YP263. The number of 1-Step Neighbors was 19+5 and 43+11. The population of Western Balkans Serbs had 4 exact matches, but only with 1st population, on 3 unique haplotypes of R-L1029>BY30715 or YP593 or Y34164 (x2), R-L1029>FGC66331 or YP417 and R-L1029>YP263. The number of 1-Step Neighbors was 27+11.

As the haplotypes of Sorbs in Lusatia could have been compared with others only using 15 Y-STR (without DYS385a/b) were taken into account the numbers of only exact matches. The prediction quality and probability surely is diminished, but possibly could give, besides Leipzig's populations, another clue with which early medieval Serbian-Sorbian tribe could have been associated. Interestingly again there's lack of matches with R-Z280/M558 and especially R-M458>L260 subclades as almost exclusively the matches are on R-L1029 subclades. Some of them are evidently only widely shared Slavic genetic background and not direct connection between West and South Slavic populations. However, the difference in R-L1029 > R-L260 ratio in Leipzig is intriguing and as such Serbian-Sorbian tribe presumably was dominantly R-L1029 with lower percentage of other R-M458 and R-Z280/M558 subclades.

Zagreb+Croatia had 2 exact matches on 2 unique haplotypes, first uncertainly of R-L260>Y2905 or R-L1029>A11460 or R-Y2613, second of R-L1280>FGC19283 or Y5647; North Croatia had 4 exact matches on 1 unique haplotype of R-L1029>YP4647 or BY30715 (x4); Central Croatia had 1 exact match of R-L260>YP5297 or some other sub-subclade; West Croatia had 1 exact match of R-Y2613; East Croatia had 3 exact mathces on 2 unique haplotypes of R-L1029>FGC66331 (x2) and R-Y2613; South Croatia and Croatian islands had zero exact matches.

Slovenia had 2 exact matches on 2 different and unique haplotypes but same Sorbian haplotype of R-Y2613 or R-YP953. The city of Ljubljana had additional 3 exact matches on 2 unique haplotypes of R-L1029>FGC66331 (x2) and R-L260>YP1337 or R-Y2613.

Bosnia and Herzegovina had 4 exact matches on 1 unique haplotype of R-L1029>YP4647 or BY30715 (x4).

Serbia (34) had also same 4 exact matches on 1 unique haplotypes of R-L1029>YP4647 or BY30715 (x4), while Serbia extended (6) had 9 exact matches on 3 different but 2 unique haplotypes of R-L1029>YP4647 or BY30715 (x8) and R-L260>YP654 or R-Z94>Z29093. The population of Western Balkans Serbs had most exact matches, 10, on 3 different but 2 unique haplotypes of R-L1029>YP4647 or BY30715 or Y34164 (x8) and R-L1029>FGC66331 or YP417 (x2).

3. Croatian detailed sub-subclades matches at FTDNA & YFull YTree

In the Nevgen calculator are predicted several, but not all, sub-subclades and sometimes with similar values of probability. For additional, at least partial, confirmation was checked database of genetic genealogical company FTDNA ("Croatian DNA Project" and "R1a project"), FTDNA's Haplotree and YFull's YTree. Unfortunately, there's a low number of Croatian genetic genealogical samples in general even less who had done Y-STR testing and even less testing of 111 markers (relevant because of DYS635 etc.) and even less NGS or WGS testing. So will be listed only subclades with existing data, and location of close or distant matches especially confirmed by Y-SNP testing.

R-Y1392/Y2902 > FGC10360/Y3226:

There exist roughly two or three ethnic Croat genetic genealogical samples out of which one or two have done NGS/WGS testing with confirmed terminal sub-subclade (in bold). However, based on Y-STR at FTDNA's R1a project, all three can be considered to be positive for R-PH3782. Both confirmed samples, one Y-SNP with terminal R-Y206680 and one Y-STR, are from Chakavian-speking Croatian islands. According to the Y-STR analysis of scientific haplotypes, R-FGC10360/Y3226's share of R-Y1392/Y2902 in Croatia is between 50-80% with an average of 60% (other part of percentage is mostly represented by East Slavic R-Y2910), in Slovenia on average is closer to 80%, in Serbian populations is 0-66% while Southeastern Slavic populations 20-50%.

* R-Y3219 (early medieval Hungarian elite "Algyo 75", Hungary, Russia, Poland, Czechia)

** R-YP1144 (Poland, Slovakia)

*** R-PH3519 (early medieval Dane Viking "Kaagarden 391", Hungary, Poland, Germany)

**** R-PH3782 (Poland, Russia, Czechia, Hungary, Germany, Austria, Slovenia, Romania; TMRCA 1650-1550 YBP)

***** R-Y206680 (unknown; TMRCA 1600 YBP)

** YP4863 (Poland, Slovakia, Ukraine, Moldova)

*** YP4966 (8th century "Sipar I26766" from Istria in Croatia, Slovakia, Hungary, Lithuania, Finland, Czechia)

**** FTB42385 (unknown; TMRCA 1740 YBP)

Slovenian matches were also found in three subclades of R-PH3782: (1) BY32501 (unknown; TMRCA 1490 YBP) > Y136823: (2) R-FT29956 (Austria; TMRCA 1380 YBP) > FT29954 (Germany; TMRCA 1130 YBP) > FTC10938 (TMRCA 600 YBP): (3) R-Y144500 (unknown; TMRCA 1280 YBP)

R-Y2613:

There exist roughly six ethnic Croat genetic genealogical samples out of which seven have done NGS/WGS testing with confirmed terminal sub-subclade (in bold). All of them can be found below phylogenetic level of R-Y2613 > Y2615 > Y2609 > Y2608 (TMRCA 1970-1850 YBP): 

* R-FTD11877 (Ukraine, Lithuania, Czechia, Germany)

** R-FT255070/Y193449 (Slovakia, Hungary, Bulgaria; TMRCA 1600 YBP)

*** R-Y332418 (Croatia; TMRCA 50 YBP)

*** R-Y275542 (Bosnia and Herzegovina, Montenegro)

* R-YP614 (Greece)

** R-YP613 (Czechia, Germany, Poland, Ukraine, Russia, Austria, Slovakia, Slovenia, Hungary; TMRCA 1700-1550 YBP)

*** R-BY103680 (unknown)

**** R-BY63552 (17th century "Gornji 35008" from Lika in Croatia)

***** R-FT174031 (Croatia; TMRCA 50 YBP)

* R-YP3929 (Czechia, Russia, Belarus of Galician-Volyn noble family, Slovakia, Hungary)

** R-Y42057 (Ukraine, medieval "Arpad 54" sample from Hungary related to Hungarian-Croatian nobility)

*** R-M12335 (Ukraine, Russia; TMRCA 1800-1620 YBP)

**** R-Y41304 (Poland, Hungary, Austria; TMRCA 1800-1570 YBP)

***** R-Y42573 (Slovenia)

****** R-FTC1189 (unknown)

******* R-Y38780 (Croatia, Bosnia and Herzegovina; TMRCA 1450 YBP)

***** R-BY125604 (Slovenia; TMRCA 1435 YBP)

* R-Y414628 (Poland; TMRCA 1350 YBP)

There have also been found R-Y2608 subclades in Serbian matches, but in Serbia, Bosnia and Herzegovina, and Croatia is only one subclade, R-YP6098 (Czechia, Belarus, possibly Moldova; TMRCA 1800-1760 YBP) > BY68536 (TMRCA 1180-900 YBP), which according some private markers, in Serbian scientific samples could make at least 20-25% of Serbian R-Y2613. Another sample was in subclade R-FT220790/Y180983 (TMRCA 1800 YBP) with matches mainly from Poland and less Slovakia, Czechia, Hungary, Slovenia. Slovenian matches are also present in several other subclades, besides FT220790/Y180983 > BY174389 (TMRCA 930 YBP), in: (1) R-BY27373 (Poland, Czechia; TMRCA 1800-1600 YBP) > BY33421 (Hungary, Austria; TMRCA 1600-1450 YBP): (2) R-YP613 > BY147823 (Czechia; TMRCA 1660 YBP) > FT367497 (Germany; TMRCA 1290 YBP) > BY110446 (Bulgaria; TMRCA 1160 YBP) > BY93569 (Germany; TMRCA 1000 YBP): and (3) R-Y2615 > Y40718 (Russia) > FGC26685 with matches from Czechia (TMRCA 1615 YBP). Slovenian subclades altogether seem mostly related to West Slavs and only partly to the Eastern Carpathians.

R-YP343 > YP340:

There exist roughly four or five ethnic Croat genetic genealogical samples of which two or three have done NGS/WGS testing with confirmed terminal sub-subclade (in bold). However, based on Y-STR at FTDNA's R1a project, it is predicted that fourth sample would be negative for all derived sub-subclades while fifth would be positive for phylogenetic line R-P278.2 > Y6662 > YP5814 (TMRCA 1900 YBP) > YP5802 (with matches mostly from Russia and less Poland, Ukraine):

* R-YP371 (Russia, Ukraine, Poland, Hungary, Austria; TMRCA 2700-2300 YBP)

** R-BY128997 (Montenegro/Bosnia; TMRCA 1650-1370 YBP)

** R-FT14429 (Russia, Ukraine, Poland, Czechia, Hungary, Estonia)

*** R-YP971 (12th century "Gornji 35012" from Lika in Croatia and "Santok 384" from Piast Poland, modern Poland, Hungary, Austria, Slovenia; TMRCA 1500 YBP)

** R-YP372 (early medieval Hungarian elite "Karos 2-18", Russia, Poland, Ukraine, Germany)

*** R-FT16632 (Ukraine, Poland, Romania)

**** R-Y10810 (Russia, Poland, North Macedonia)

***** R-YP374 (Hungary, Slovakia)

****** R-FT23148 (Poland, Russia, Slovakia, Hungary, Czechia, Slovenia, Austria, Germany, Finland, Denmark)

******* R-FT198060 (Russia; TMRCA 1400 YBP)

******* R-FT161833 (Russia; TMRCA 1560 YBP)

******** R-FT192944 (Bosnia and Herzegovina, United States)

********* R-Y239903 (Croatia; TMRCA 1200 YBP)

There has also been found R-YP371 subclade R-Y244926 > FT14429 > Y110177 > Y81700 > Y85703 (TMRCA 1800 YBP) in a Serbian match from Bosnia and Herzegovina with distant matches from Hungary, Russia, Ukraine, Finland and Estonia.

R-L1280:

There exist roughly one or three ethnic Croat genetic genealogical samples, probably of a single family, but all have done NGS/WGS testing with confirmed terminal sub-subclade (in bold):

* R-Y5647

** R-YP6343 (Russia; TMRCA 1600-1500 YBP)

*** R-Y98821/Y105217 (Bosnia and Herzegovina, Serbia; TMRCA 1400 YBP)

**** R-Y98520 (unknown; TMRCA 1250 YBP)

***** R-FT84144 (TMRCA 150 YBP)

** R-FT148265/FT149101 (Russia, Ukraine, Czechia, Denmark, Bulgaria)

*** R-Y51639/YP611 (Germany, Denmark; TMRCA 2150 YBP)

**** R-YP3987 (Serbia, Bosnia and Herzegovina, Albania)

***** R-FTB69732 (Serbia, Bosnia and Herzegovina, Albania; TMRCA 1500 YBP)

Among the South Slavs can be also found R-FGC11555 (Ukraine, Belarus, Russia, Czechia, Germany) > Y174060/A19673 (Poland, Turkey; TMRCA 1630-1300 YBP). Another subclade R-FGC19283 > YP1448 and YP6061 is mainly common in Poland, but with some samples from Ukraine, Belarus and Germany as well.

R-Y4459:

There exist roughly two ethnic Croat genetic genealogical samples but from Bosnia and Herzegovina. Both have done NGS/WGS testing which confirmed terminal sub-subclade (in bold):

* R-YP617 (Russia, Belarus, Ukraine, Lithuania, Poland, Czechia)

** R-Y38448/BY123126 (Bulgaria; TMRCA 1650-1470 YBP)

*** R-BY169316 (Serbia; TMRCA 1650-1300 YBP)

**** R-Y155362 (unknown; TMRCA 950 YBP)

**** R-BY170000 (Montenegro; TMRCA 750-620 YBP)

A subclade R-YP617 > Y29965 > Y88926 has also been found in ancient sample "R9673" from Viminacium, Serbia (with contemporary distant matches from Denmark, Sweden, Poland and Slovakia).

Other R-Z280/M558 subclades:

As for other subclades, for now without Croatian genetic genealogical sample, here will be listed those with samples by neighboring Slovenians, Bosnians and Serbians because due to related South Slavic genetic background the Croatian could belong to them as well: (1) R-YP953 > YP951 > YP4659 (Russia, Ukraine, Poland, Latvia, Finland; TMRCA 2350-1550 YBP) > YP6186 (Bulgaria, Romania; TMRCA 2230-1300 YBP) > BY99654 (Bosnia and Herzegovina, Serbia; TMRCA 1650-1200 YBP): (2) R-YP4278 (Ukraine, Russia, Czechia, Hungary, Finland; TMRCA 2400-1700 YBP) > Y109474/BY30749 (Bulgaria; 1940-1300 YBP) > BY30743 (Serbia, Montenegro, Bosnia and Herzegovina; TMRCA 1000-800 YBP): (3) R-L366 > FT36801 (Montenegro, Russia) > FTB42580 (Russia, Silesian Poland; TMRCA 2100 YBP) > FTC25856 (Serbia, Kosovo; TMRCA 1350 YBP): (4) R-YP270 > CTS4648 > YP1408 > Y13891 > BY105638 > BY116359 (Montenegro, Silesian Poland; TMRCA c. 2200 YBP): (5) R-YP582 > YP578 (ancient sample "R6759" from Viminacium, Serbia and Poland, Ukraine, Russia, Estonia, Finland; TMRCA 2000 YBP): (6) R-YP1034 no sample, present in Lithuania, Latvia, Ukraine, Russia, Poland, Sweden: (7) R-FT14137/Y167503 no sample, present in Poland, Ukraine, Russia, Hungary, Germany: (8) R-YP420 has no sample, present in Belarus, Lithuania, Ukraine, Russia, Germany: (9) R-Y10805 has no sample, present in Finland, Czechia, Great Britain: (10) R-YP6228/YP6213 has no sample, present in Ukraine, Hungary, Austria, Germany: (11) R-YP1019 has no sample, present in Russia, Ukraine, Latvia, Lithuania, Poland.

R-L260:

There exist only five-six ethnic Croat genetic genealogical samples for clade R-M458, specifically R-L260, but one case includes three samples who done NGS/WGS testing which is probably a study of a single family with confirmed terminal sub-subclade (in bold). However, based on Y-STR at FTDNA's R1a project, it is predicted that fourth-fifth Y-STR sample would be also positive for subclade R-YP1337 but matched with haplotypes from Ukraine, Poland, Czechia and Germany of sub-subclade R-FT124486 > BY100987 (TMRCA 1800-1250 YBP). Sixth sample is positive for subclade R-YP256 > Y2905. According to the 23 and 17 Y-STR analysis of scientific haplotypes, R-YP1337 share is between 33-75% with an average of 54-66% in Croatia. It has similar percentage in Slovenia (66%), Bosnia and Herzegovina (100%) and less in Serbian populations (0-33%), but higher in the population of Bulgaria (33%) and Bulgaria+Romania (100%).

* R-YP1337 (mainly Russia, Ukraine, Poland)

** R-FT377312 (9th century "Brekinjova Kosa I26748” from continental Croatia, Czechia, Poland, Slovenia; TMRCA 1850 YBP)

** R-Y300209 (Poland, Russia, Belarus, Czechia)

*** R-Y132937/BY35659 (12th century "Płońsk 323" Piast Masovia, Russia, Ukraine, Belarus, Poland, Czechia; TMRCA 1680-1500 YBP)

**** R-Y132940/BY35646/BY35603 (Croatia; TMRCA 200 YBP)

* R-YP256

** R-YP254

*** R-Y2905

**** R-Y23110 (Poland, Slovakia, Ukraine, Russia, Belarus, Czechia, Germany; TMRCA 1900 YBP)

***** R-FTE34475 (Germany; TMRCA 1350 YBP)

A subclade FT377312 (Czechia, Poland; TMRCA 1850 YBP) was found in Slovenia. As for other R-L260 subclades, R-Y2905 > BY25698 > FT13267 (TMRCA 1300 YBP) > Y167440 (TMRCA 1300 YBP) > Y281186 was also confirmed in a Serbian sample from Vojvodina with closest match from West Slovakia while others from Southern-Southeastern Poland and Southwestern Ukraine.

Other R-M458 subclades:

According to the 23 and 17 Y-STR analysis of scientific haplotypes, R-L1029 seems to be very diverse in Croatia. However, likewise other subclades, for now without Croatian genetic genealogical sample, here will be listed those with samples by neighboring Slovenians, Bosnians and Serbians because due to related South Slavic genetic background the Croatian could belong to them as well: (1) R-L1029 > YP417 > YP418 > YP728 > YP6047 (Russia, Estonia, Sweden) > FT285270 (Serbia, Bosnia and Herzegovina, Croatia, Ukraine, Romania, Albania; TMRCA 1610-1550 YBP) and YP418 > FTB20451 (Russia) > BY71087 (Poland; TMRCA 1980-1550 YBP) > FTB3834 (Croatia, Montenegro; TMRCA 1435-950 YBP): (2) R-A11460 (Poland, Ukraine) > BY202471 > BY202644 (Poland, Serbia; TMRCA 1550 YBP) > Y345540 (North Macedonia; TMRCA 1100 YBP).

4. Conclusion

The majority of Croatian R-Z280/M558, which makes 70-80% share of R1a in Croatia, with predicted subclades on 17 and 23 Y-STR, particularly, R-Y1392/Y2902>FGC10360/Y3226, R-Y2613>Y2608, R-YP343>YP340>YP371 and P278.2 (which together roughly make 65-75% share of R-Z280/M558), but also R-L1280 as well as rarer subclades like R-Y4459 and others show that they are mostly related to the East Slavs and geographically to the Eastern Carpathians. R-M458, which makes 15-25% share of R1a, is mostly of Eastern-Western Slavic subclade R-L1029 or equal percentage with R-L260, but the majority of R-L260's predicted sub-subclade is also mostly Eastern Slavic R-YP1337 (60%).

R-Y1392/Y2902 (27-32%) is mainly represented by one subclade R-FGC10360/Y3226 (50-80%) which is also called "Carpathian-Russian" or "Volgo-Carpathian" due to its high concentration on the border of the Eastern and Western Carpathians and European Russia (migration apparently went from the east to the northeast and southwest). The concentration shows how the migration went from the Eastern Carpathians through the Pannonian Plain. R-Y2613 (24%) is exclusively or mainly represented by one subclade R-Y2608, which is also called "Carpathian-Dalmatian" because of the same concentration in the Carpathians from where it migrated. R-YP343>YP340 (13-17%) is mostly represented by a subclade R-YP371 and less of R-P278.2 (currently known closest matches on terminal SNPs are in Russia, Ukraine and Poland). R-L1280 (11%) is exclusively or mainly represented by one subclade R-Y5647 that migrated along the Eastern Carpathians. R-L1029 is quite diverse with for now unconfirmed matches. R-L260 is mainly represented by one subclade R-YP1337 (33-75% with an average of 54-66%) with the closest matches in Russia, Ukraine and the Czech Republic, and generally significantly represented in Western Ukraine and Northeastern Hungary. When are added to the list subclades of I2-CTS10228>Y3120 (I-S17250>PH908, Z16971 and I-Y4460), they make combination of Slavic paternal lineages of early Slavs who settled in the territory of modern-day Croatia.

All the data, specifically regarding historical tribe of Croats, arguably confirmed direct connection between contemporary Croats and contemporary population of Rusyns and broader Slavic-speaking population living on the border of Western Ukraine, Southeastern Poland, Eastern Slovakia and Northeastern Hungary. It confirmed that the contemporary Rusyns are descendant of the early medieval White Croats. It confirmed main route of migration of the White Croats and their tribal alliance to modern day Croatia, being from north of Eastern Carpathians, mainly not around Kraków and West of it yet East of Kraków in Southeastern Poland and Western Ukraine, through the Carpathian i.e. Pannonian Basin to the historical regions of Lower Pannonia and Dalmatia, but due to genetical, historical, archaeological and ethnolinguistic evidence most probably also parts of neighboring countries of modern day Croatia. The paternal population of Croatia is genetically relatively too much homogenous to be considered as product of two separate Slavic early medieval migrations (first of the late 6th century unnamed Avaro-Slavs and second of the 7th century Croats). It is impossible for now to differentiate these two migrations, even on dialectological level (as both Kajkavian-speaking region and Chakavian-speaking islands show direct connection to the Eastern Carpathians). 

Paradoxically for dual migration theory, it would imply that happened two migrations from the roughly same region of Carpathians (Galicia) where are historiographically and archaeologically located the Carpathian Croats. The dual migration theory is obsolete as genetical data confirms that the ancestors of contemporary Croats were part of, actually, were those Slavs that arrived in the first massive wave to Pannonia and Dalmatia with the Pannonian Avars in the end of the 6th century. The data confirms there did not happen any other additional, separate or major wave of Croats in the 7th century yet confirms that such a theory is based solely on the political narrative written in the Byzantine De Administrando Imperio (10th century). The emergence of the Croats, in the political narrative, is rightly described by historians as merely a rebellion against the Avars of already arrived and settled Slavs i.e. Croats in which the Byzantine emperor was partially involved. They were enough well organized and strong to successfuly fought and won against the Avars elite in the early 7th century, but also receiving recognition by the Western and Eastern Roman powers, forming centre of Croatian state and helped form adject polities, related to White Croatian & Lechites tribal alliance, in the Western Balkans.

Instead of writing additional remarks can be said that the results of the Y-STR and Y-SNP analysis in 2023 confirmed genetical conclusions which were predicted over ten years ago, while historiographical and arhcaeological decades ago, hence will be cited for the end:

"Cluster 6.K is relatively frequent in Slovakia, South-Eastern Poland and Western Ukraine, but also in Croatia and Slovenia. This cluster maybe associated with an "Old-Croatian" ancestry, as some people believe that the so-called White Croats (possibly closely related to the Croats arriving to Croatia) used to live in the North-Eastern Carpathian region (where this cluster is relatively common today)." (Michal Milewski, 2013).

"When assuming that the so-called White Croatia (ie. a region encompassing SE Poland and the neighbouring part of Ukraine) had anything to do with the hypothetical Old Croats migrating from the Carpathian region to Western Balkans, one can also suspect that clade Y2613 was one of the major Y-DNA clades present in those hypothetical Early Medieval Old Croats who are supposed to have initially lived somewhere north-east of the Carpathian range. In addition to Y2613, there are of course many more "Slavic" subclades that could have been quite common among those Old Croats, and this includes I2a-CTS10228, R1a-Y2902>Y3226, R1a-P278.2 and R1a-YP371." (Molgen forum, 2016).

"Subclade YP3929 is a part of a much larger (and older) clade Y2613 that is sometimes called "Carpathian-Dalmatian", as it seems to be the most frequent in the Northern Carpathian region (including SE Poland, Slovakia and Hungary) and in the West Balkans (in Slovenia and Croatia), although it is also not uncommon in other countries / regions where Slavic people live today (or where they are known to have migrated in the past). Clade Y2613 is the subject of the "Old Croatian" tribe / population, a group believed to be ancestral to both the so-called White Croats and the West Balkan Croats, although this seems to be very speculative. If you believe in the most commonly accepted hypothesis, the YP3929 were born in the encompassing region of Southern Belarus and Northern Ukraine, where they were taking part in the formation of the Early Slavic (or Proto-Slavic) community that has expanded in different directions (with people from the Y2613 clan, mostly contributing to a tribe that migrated westwards towards SE Poland and then towards West Balkans, although there are several exceptions from this general rule, as there are also many small lines under Y2613 / Y2617 / Y2609 / Y2608 that apparently migrated north or east, probably as a part of some other Early Slavic tribes. According to YFull, the most recent common ancestor of all modern YP3929 lineages lived about 2,000 years ago, so long before the early stages of the expansion of the Early Slavs, and thus there was plenty of time for different sublineages to join the different Early Slavic tribes, although the most of the YP3929 lineages seem to be associated with an unknown Early Slavic (Old Croatian?) tribe that migrated west and south-west." (Michal Milewski, 2017).

Skole Beskids National Nature Park in Western Ukraine (Wikimedia Commons)

The Croats arrival at the Adriatic Sea by Oton Iveković, 1905 (Wikimedia Commons)