Genetic study The Genetic Variability of Present-Day Bulgarians Captures Ancient and Recent Ancestral Contributions

[Tautalus]

ABSTRACT

Objectives
Thanks to its pivotal crossroad position, Bulgaria played a fundamental key role during all the migration processes that interested the continent through time. While the genetic variability of the country has been deeply investigated using uniparental markers, previous genome-wide autosomal-based surveys mainly consisted of wider-range analyzes on Europe and the whole Balkan Peninsula. Here, we specifically focused on the Bulgarian population to recapitulate the main patterns of genomic variation and the major events that shaped the present-day genetic landscape.

Methods
A total of 112 samples from seven highly representative areas of present-day Bulgaria were collected and genotyped for approximately 720 K genome-wide SNPs, and integrated with previously generated genomic data from wide modern and ancient reference panels to explore fine-scale relationship patterns and detail ancestral contributions.

Results
In addition to the combination of ancient ancestries related to the early Mesolithic hunter-gatherers, Neolithic farmers, and Bronze Age Steppe pastoralists, both haplotype-based analyzes on modern populations and the comparisons with ancient genomes suggest the contribution of population processes that have occurred after the Roman rule and during the Medieval period in shaping the current Bulgarian genetic pool.

Conclusions
Our results align with previous evidence highlighting the impact that some historical events may have had not only in contributing to the ethnical and socio-cultural richness of present-day populations, but also in participating in the formation of the current genomic landscape. By providing new data from modern highly-representative samples, this study integrates further research to provide a comprehensive overview of the genetic history of Bulgaria.

The Genetic Variability of Present-Day Bulgarians Captures Ancient and Recent Ancestral Contributions

(A) PCA
(B) Average proportions of ancestral components. (yellow: Sardinian/South-Western European, red: North-Eastern European, green: Caucasian, blue: Middle-Eastern)

(A) Timeline showing the chronological distribution of ancient Bulgarian individuals
(B) PCA - ancient samples projection into modern individuals PCA
(C) Ancient admixture proportions

 

[Pax Augusta]

Thanks for sharing this, Tautalus.
I took a quick look, and I’ll read it more carefully when I have time. A few things caught my attention right away.

It’s surprising that in a study about Bulgarians, the PCA only uses one set of Greek samples. From what it's written in the Supp info these samples are from previous study such as Kushniarevich et al (2015), so they are samples from Thessaloniki, Macedonia, plus other samples from Macedonia (there are two academic sets from Macedonia), other samples labelled Central Greece and Peloponnese. But there are no samples from the Aegean Islands, which doesn’t make any sense.

Also, the study found that the Levant_Natufian has been in Bulgarian samples since the Neolithic period, and it’s still there in modern Bulgarians. Did they use pure Natufian or Levant_PPNB samples for this? And why isn’t there any Iran_N found?

 

[Valerius]

Also, the study found that the Levant_Natufian has been in Bulgarian samples since the Neolithic period, and it’s still there in modern Bulgarians. Did they use pure Natufian or Levant_PPNB samples for this? And why isn’t there any Iran_N found?

Continuity with the Neolithic period is impossible. Although that admixture existed back in the period, it must have been reintroduced at a very late stage, likely in the last 2000 years.

 

[Bill7]

This study supports barely 12-15% thracian dna in modern bulgarians and 56% ancestry derived from an eastern european source.Is there really some much slavic in bulgarians?

 

[Valerius]

This study supports barely 12-15% thracian dna in modern bulgarians and 56% ancestry derived from an eastern european source.Is there really some much slavic in bulgarians?

The 56% in the results is the entire North European admixture of which likely 37% is Slavic per se, while the rest is coming from other sources that had Northern components in them. Judging by the haplogroup distribution, there are plenty of Germanic and Illyrian-derived lineages that might have introduced additional Northern admixture. The Thracian DNA is likely about 19% as seen in the Olade et al. This study have actually replicated the methodology of Olade et al. however, the Iron Age Thracian admixture appears lower this time.

 

[Vitruvius]

I'm having major doubts of Natufian/PPNB in any of these chronological eras.

 

[Pax Augusta]

Continuity with the Neolithic period is impossible. Although that admixture existed back in the period, it must have been reintroduced at a very late stage, likely in the last 2000 years.

I did not write anywhere about continuity with the Neolithic.

I'm having major doubts of Natufian/PPNB in any of these chronological eras.

Using Natufian/PPNB can be very misleading, because it can inflate the results as PPNB is a mix of Natufian and ANF/EEF.

 

[Riverman]

Haplogroups predictions:

Dati_BULGARI Haplotypes Copy.xlsx

docs.google.com

From the Genarchivist thread:

Bulgaria thread

 

[Vitruvius]

Using Natufian/PPNB can be very misleading, because it can inflate the results as PPNB is a mix of Natufian and ANF/EEF.

I agree, but there is also the fact that if you use Neolithic South Caucasian ancestry as a source, even in tandem with Levant PPNB the PPNB will disappear in all European populations. The better fit is not the migration of neolithic Levantine ancestry to southern Europe but instead neolithic Caucasian ancestry. Thanks to Skourtanioti et al. 2023 we know for a fact that Anatolia was the mediator of this southern caucasian input.

 

[Vitruvius]

This is also not even going into the fact that the models use neolithic Levantine ancestry as a source of ancestry for then contemporary Bulgarian neolithic EEFs.

This is absurd as we know that the entirety EEF ancestry is Barcin Neolithic + European HG derived. More realistically these authors and many others need to stop using CHG as a caucasian source of input to europeans as all or nearly all caucasian ancestry in europe stems from post neolithic movements such as steppe and anatolian population expansions.

 

[Thucydides enjoyer]

Cords of the samples

Bulgari_Rodopi:LG803(RD01_Belovo),0.119514,0.139128,0.024513,-0.001938,0.026466,-0.001673,0.004465,0.001154,0.001023,0.005467,0.003573,0.000749,-0.002973,0.010872,-0.012351,0.005171,0.013951,-0.00038,0.003645,-0.001251,-0.001747,-0.001978,0.006902,-0.002048,0.001078
Bulgari_Rodopi:LG804(RD02_Bansko),0.121791,0.148267,0.034695,-0.001292,0.02739,0.00753,0.004465,0.010153,-0.001636,0.002734,0.002761,-0.003747,0.000892,0.012937,-0.014658,-0.018563,-0.008475,-0.00266,0.001257,-0.005628,-0.015847,-0.004328,0.00456,0.006025,0.001557
Bulgari_Rodopi:LG805(RD03_Yakoruda),0.118376,0.146236,0.032055,0.005814,0.033545,0.007809,0.003055,0.005307,-0.001227,-0.002005,0.000162,0.001649,0.002379,0.015964,-0.015336,-0.015778,-0.004172,-0.000253,0.009553,-0.002876,-0.008485,0.005688,0.003204,0.000964,0.002515
Bulgari_Rodopi:LG819(RD17_Starcevo),0.134311,0.136081,0.039221,0.006137,0.029236,0.00502,0.005875,0.011076,-0.00225,0.003098,0.000974,-0.002398,0.004311,0.01734,-0.019272,-0.014983,-0.001695,-0.002534,0.006411,-0.001626,-0.009109,-0.002597,0.004067,-0.00482,0.005389
Bulgari_NW_BG:LG821(NW01),0.120652,0.135065,0.026398,-0.005491,0.025235,0.001952,0.006345,0.009692,-0.008181,0.009112,0.004547,-0.004046,0,0.019818,-0.017101,-0.017767,-0.008084,0.003801,0.005656,-0.009379,-0.01123,0.004575,0.007272,0.001566,-0.000958
Bulgari_NW_BG:LG823(NW03_Tolovica),0.121791,0.138112,0.034695,0.021964,0.030467,0.002789,0.002585,0.003,0.00225,-0.006196,-0.00065,-0.002847,0.00446,0.015138,-0.013979,-0.006099,0.012126,0.001647,0.005782,-0.004127,-0.013601,0.001113,0.003697,-0.002169,0.000838
Bulgari_NW_BG:LG830(NW10_Damyanovo),0.120652,0.137096,0.030547,0.00646,0.034776,0.000837,0.00423,0.01223,0.000818,-0.001276,0.000974,-0.004346,0.013379,0.01445,-0.012215,0,0.007432,-0.006588,0.005154,0.00075,-0.007487,0.004204,0.007272,0.000723,-0.005628
Bulgaria_NW_BG:LG832(NW12_Borovtsi),0.124067,0.128972,0.036204,0.013889,0.022773,0.006414,0.002585,0.00923,-0.004295,0.000547,-0.008931,-0.001948,0.003717,0.015414,-0.016965,-0.001856,0.003781,-0.005954,0.008799,-0.001626,-0.004243,-0.012984,0.006409,0.00482,0.002155
Bulgaria_NW_BG:LG834(NW14_Lehchevo),0.118376,0.131003,0.035826,0.002584,0.031083,0.000558,0.00047,0.005307,0,-0.002369,0.001137,0.001049,0.008028,0.015001,-0.011265,-0.016441,-0.004694,0.009502,0.004777,-0.000875,-0.014599,0.00272,-0.006902,-0.004338,-0.005029
Bulgaria_NW_BG:LG835(NW15_Lehchevo),0.127482,0.138112,0.035826,0.002261,0.02462,0.01004,0.003055,0.005307,0.008181,0.003645,0.002436,-0.002398,0.002973,0.012524,-0.012079,-0.001591,0.004824,-0.00076,0.005656,-0.004252,-0.008984,-0.000618,0.002835,0.001446,0.001197
Bulgaria_NW_BG:LG836(NW16_Septemvriitsi),0.120652,0.138112,0.029038,0.007429,0.021542,0.004183,0.0047,0.009923,-0.001841,0.007107,0.000974,0.000899,-0.000446,0.001927,-0.009365,-0.008751,-0.005346,-0.000253,0.005531,-0.009379,-0.002995,-0.001113,0.003821,-0.005181,-0.000838
Bulgaria_Kapantsi:LG848(KP03_Sadina),0.120652,0.135065,0.017725,0.004199,0.020619,0.005857,0.000705,-0.000692,-0.004909,0.004374,0.006983,-0.006744,-0.002825,0.017753,-0.009365,-0.000663,0.006389,0.003167,0.001634,-0.009129,-0.01123,-0.005935,0.001356,-0.000602,-0.010179
Bulgaria_Vayatsi:LG851(VY01_Golitsa),0.124067,0.131003,0.025644,0.01292,0.029852,0.011156,0.00376,0.004846,0.001023,0.004738,-0.003735,-0.003297,0.002081,0.007156,-0.006786,-0.000663,0.013169,-0.004687,0.000503,-0.006503,-0.008485,-0.00371,0.002835,0.00241,-0.003353
Bulgaria_Vayatsi:LG852(VY02_Golitsa),0.119514,0.144205,0.017348,-0.010013,0.018465,-0.001116,0.006815,0.001154,-0.005931,0.005103,-0.000812,-0.000899,-0.002973,0.007156,-0.015879,-0.009149,0.001956,-0.000253,0.002891,-0.006378,-0.01123,0.001607,-0.002588,0.001205,0.005748
Bulgaria_Vayatsi:LG855(VY05_Erkech),0.119514,0.13405,0.022627,0.001615,0.025235,0.003626,0.003995,0.006,-0.001432,0.008018,-0.00341,-0.004346,0.003865,0.011423,-0.009908,-0.005436,-0.007432,0.002407,0.00729,-0.012006,-0.012104,-0.000742,0.007765,0.00494,-0.000479
Bulgarian_Vayatsi:LG912(VY06_Erkech),0.1161,0.137096,0.025644,-0.009044,0.018465,-0.001394,0.001645,0.00923,-0.0045,0.005649,-0.005359,0.001199,0.00669,0.004954,-0.006243,0.018297,0.017732,-0.004687,0.005154,0.004752,-0.009358,0.003462,0.005053,0.00012,0.007424
Bulgaria_Thrace:LG857(TR02_Tunkovo),0.113823,0.131003,0.02489,0.003876,0.019696,0.000837,-0.000705,0.005077,-0.003272,0.005103,0.003248,-0.001948,-0.0055,0.002202,-0.014115,0.005436,0.024382,-0.004434,0.000628,-0.002376,-0.012228,0.006183,0.005546,0.006025,-0.002874
Bulgaria_CentralBalkans:LG861(CB01_Lesicheri),0.114961,0.138112,0.02225,-0.003553,0.017234,0.004183,0.005875,0.010384,-0.00634,0.005285,0.002436,-0.002398,-0.000892,0.001376,-0.013029,-0.004773,-0.003129,-0.000887,0.002765,-0.003752,-0.005366,-0.002226,0.00037,-0.004458,0.002155
Bulgaria_CentralBalkans:LG863(CB03),0.119514,0.136081,0.02753,-0.004199,0.022466,-0.002231,0.002585,0.002538,-0.001227,-0.002005,-0.001786,-0.003597,0.002527,0.008533,-0.010315,-0.022275,-0.006519,-0.007475,0.000377,-0.006628,-0.008485,0.001484,-0.003944,-0.000361,0.002275
Bulgaria_CentralBalkans:LG864(CB04_Bebrovo),0.114961,0.136081,0.017348,0.002907,0.029852,0.005299,0.000705,0.003692,-0.000818,0.007107,0.003573,-0.005095,0.004757,0.010735,-0.015608,0.0118,0.019036,-0.004687,0.002891,0.007379,-0.009608,-0.003833,0.003328,-0.006868,-0.003952
Bulgaria_Central_Western_BG:LG871(CW05_Kosacha),0.113823,0.131003,0.026021,0.001615,0.022466,-0.005857,0.00329,0.004384,-0.003272,0.004374,-0.000974,0.005695,-0.004162,0.007569,-0.016015,-0.010342,-0.005346,-0.00228,0.002765,-0.010505,-0.01123,0,0.00456,0.003374,0.006706
Bulgaria_Central_Western_BG:LG874(CW08_Slatina),0.117238,0.136081,0.017348,-0.000969,0.008617,-0.001952,0.00423,0.003461,-0.002863,0.002916,-0.002436,-0.00045,-0.001933,0.009083,-0.012758,-0.004906,-0.007562,0.001014,0.002891,-0.008254,-0.004866,0.010387,0.006409,0.005181,0.002275
Bulgaria_Central_Western_BG:LG876(CW10_Banya),0.122929,0.133034,0.03017,-0.001938,0.030775,-0.002231,0.01081,0.005769,-0.001636,0.00328,-0.001624,0.001049,0.000149,0.000826,-0.018051,0.008618,0.025425,0.003167,0.006536,-0.002251,-0.008984,-0.004822,0.010476,0.00241,0.001317
Bulgaria_Central_Western_BG:LG878(CW12_Mirovyane),0.119514,0.125926,0.025644,0.008075,0.025235,0.001673,0.005405,0.007154,-0.000205,0.003827,0.002436,-0.003597,0.005054,0.008257,-0.005429,0.005834,0.01017,-0.005448,0.006913,-0.00075,-0.003993,-0.000989,0.000986,0.006025,0.001078
Bulgaria_Central_Western_BG:LG882(CW16_Skravena),0.121791,0.137096,0.035449,0.007106,0.020004,0.008925,0.006345,-0.000462,-0.00409,0.004009,-0.005359,0.003447,-0.007879,0.01679,-0.012758,-0.011668,-0.004563,-0.007475,0.002514,-0.011881,-0.007362,-0.000742,0.002835,-0.006145,0.002395
Bulgaria_Central_Western_BG:LG884(CW18_Bov),0.114961,0.144205,0.022627,-0.005491,0.025543,0,0.005405,0.006231,0.001432,0.005649,0.00065,-0.001199,0.001041,0.010872,-0.013436,-0.006099,-0.007953,-0.003167,0.006788,-0.005253,-0.003244,0.005688,0.003697,-0.005061,-0.001557
Bulgaria_Central_Western_BG:LG886(CW20_Rebrovo),0.122929,0.139128,0.020365,0.002261,0.024004,0.000558,0.011045,0.002077,-0.004704,0.001458,-0.000487,-0.001948,0.003122,0.003853,-0.012758,0.006762,0.014473,-0.002534,0.00264,-0.002376,-0.004866,0.003957,0.000739,-0.006868,-0.008143
Bulgaria_Thrace:LG888(TR07_Cherna_Mogila),0.117238,0.140143,0.01961,-0.005491,0.027082,0.000837,0.00517,0.005307,0.005727,0.013121,0.007795,-0.001499,0.003271,0.01445,-0.016422,-0.013922,-0.008996,-0.003167,0.004399,-0.004502,-0.009109,0.00371,-0.002095,-0.000964,-0.011256
Bulgarian_Thrace:LG892(TR11_Boyanovo),0.12862,0.138112,0.02225,-0.001292,0.017542,-0.005299,0.00094,0.005077,-0.006545,-0.002551,-0.00406,-0.002248,0.002676,0.015827,-0.019679,-0.011668,-0.008475,0.004434,0.006662,-0.003126,-0.007112,-0.004081,0.00456,-0.006386,-0.006107
Bulgarian_Thrace:LG893(TR14),0.114961,0.136081,0.014331,-0.006783,0.016311,0.005578,0.00893,0.001385,-0.005522,0.007836,0.00065,0.005845,0.001933,0.010597,-0.019544,0.008486,0.017471,0.003801,0.004902,-0.005753,-0.005241,0.001237,0.001849,0.005061,-0.012454
Bulgarian_Thrace:LG896(TR17_Lyubenova_Mahala),0.112685,0.138112,0.023381,0.003553,0.022773,-0.000837,0.00423,0.004615,-0.002045,0.000547,-0.001786,-0.001798,0.000149,0.01101,-0.006786,-0.012861,-0.01356,0.002407,0.006913,-0.002001,0.000998,0.001731,-0.000246,-0.002892,-0.000599
Bulgarian_Thrace:LG899(TR20),0.118376,0.150298,0.018856,-0.008398,0.020311,-0.006136,0.006815,0.003,-0.008181,0.008747,0.000325,0.001649,-0.004162,0.008533,-0.016151,-0.015115,-0.005867,-0.004307,0.004274,-0.01013,-0.003619,0.00371,0.001479,0.000361,-0.005987
Bulgarian_Central_Bulgaria:LG900(CB07_Drenta),0.111547,0.117801,0.020742,-0.002907,0.028621,-0.003347,-0.000235,0.005538,0.003068,0.003827,0.006333,-0.002398,0.000892,0.007156,-0.012079,0.014452,0.021122,0.006841,0.000628,0.001751,-0.008235,-0.000371,0.011339,0.008676,-0.007903
Bulgarian_Central_Bulgaria:LG901(CB08_Drenta),0.1161,0.135065,0.021873,-0.00969,0.022466,-0.001116,0.00094,-0.001385,0.002045,0.007289,0.005034,-0.001049,0.003122,0.00812,-0.011808,0.002917,0.00691,0.004307,0.00264,-0.009004,-0.002121,-0.001855,0.002958,-0.004338,-0.002155
Bulgarian_Central_Bulgaria:LG902(CB09_Dedina),0.1161,0.13405,0.024513,-0.001615,0.031698,-0.002789,0.006345,0.009,-0.011453,0.011299,-0.003897,-0.000599,-0.000297,0.008808,-0.014522,-0.004906,0.00665,0.000507,0.000503,0.001251,-0.009858,-0.001484,0.008134,-0.005904,-0.007185
Bulgarian_Central_Bulgaria:LG905(CB13_Gabrovo),0.117238,0.141159,0.019233,-0.007106,0.025851,-0.001673,0.003525,-0.001385,0.001841,0.005285,-0.001137,-0.003447,0.003271,0.009634,-0.017101,-0.004243,0.007302,-0.004054,0.006034,-0.002376,-0.00287,-0.002968,0.008627,-0.004579,0.001916
Bulgarian_Central_Bulgaria:LG907(CB15_Paskalevets),0.125205,0.139128,0.026021,-0.010336,0.016003,-0.006693,0.00423,0.002538,-0.005727,0.009294,-0.000162,-0.001349,-0.003419,0.003441,-0.014929,0.001591,0.01708,0.001774,0.003017,-0.005503,-0.010981,-0.003462,0.00419,-0.005061,-0.001676
Bulgarian_Central_Bulgaria:LG908(CB16_Sindjirtsi),0.121791,0.142174,0.028284,0.00323,0.023389,-0.001673,0.003995,-0.003,-0.002863,0.00328,-0.001624,-0.002847,0.006392,0.018166,-0.015879,0.001061,0.012778,0.003041,0.006411,-0.008754,-0.011105,0.008161,0.008751,-0.001566,0.000718