Y-Chromosome Diversity in Modern Bulgarians: New Clues about Their Ancestry

Sena Karachanak,Angel S Galabov,Desislava Nesheva,Yordan Yordanov,Viola Grugni,Valeria Carossa,Draga Toncheva,Antonio Torroni,Simona Fornarino,Vincenza Battaglia,Ornella Semino,Nadia Al-Zahery

doi:10.1371/journal.pone.0056779

Abstract

To better define the structure and origin of the Bulgarian paternal gene pool, we have examined the Y-chromosome variation in 808 Bulgarian males. The analysis was performed by high-resolution genotyping of biallelic markers and by analyzing the STR variation within the most informative haplogroups. We found that the Y-chromosome gene pool in modern Bulgarians is primarily represented by Western Eurasian haplogroups with ∼ 40% belonging to haplogroups E-V13 and I-M423, and 20% to R-M17. Haplogroups common in the Middle East (J and G) and in South Western Asia (R-L23*) occur at frequencies of 19% and 5%, respectively. Haplogroups C, N and Q, distinctive for Altaic and Central Asian Turkic-speaking populations, occur at the negligible frequency of only 1.5%. Principal Component analyses group Bulgarians with European populations, apart from Central Asian Turkic-speaking groups and South Western Asia populations. Within the country, the genetic variation is structured in Western, Central and Eastern Bulgaria indicating that the Balkan Mountains have been permeable to human movements. The lineage analysis provided the following interesting results: (i) R-L23* is present in Eastern Bulgaria since the post glacial period; (ii) haplogroup E-V13 has a Mesolithic age in Bulgaria from where it expanded after the arrival of farming; (iii) haplogroup J-M241 probably reflects the Neolithic westward expansion of farmers from the earliest sites along the Black Sea. On the whole, in light of the most recent historical studies, which indicate a substantial proto-Bulgarian input to the contemporary Bulgarian people, our data suggest that a common paternal ancestry between the proto-Bulgarians and the Altaic and Central Asian Turkic-speaking populations either did not exist or was negligible.

Highlights

Bulgaria is situated in the eastern part of the Balkan Peninsula, on the shores of the Black Sea linking Southeastern Europe to the Eurasian steppe as well as Anatolia and the Aegean islands
Third in frequency is the common Eurasian haplogroup R-M17, which was found in 17.5% of Bulgarians, with 42.9% of them belonging to the European specific R-M458 sub-clade [36]
The variation among populations from the former administrative provinces was small and of uncertain significance (0.38%, p

Summary

Introduction

Bulgaria is situated in the eastern part of the Balkan Peninsula, on the shores of the Black Sea linking Southeastern Europe to the Eurasian steppe as well as Anatolia and the Aegean islands. It lies on the postulated pathway that introduced modern humans into Europe in the Upper Paleolithic as attested by the series of assemblages at Bacho Kiro and Temnata Dupka Caves, which are considered signs of the Aurignacian culture expansion , 40 kya [1,2,3]. It appears to have remained habitable even during the Last Glacial Maximum (LGM) [4] fuelling different expansion routes of post-glacial re-colonization. Two other populations playing an important role in the Bulgarian ethnogenesis were the Slavs and the proto-Bulgarians, who arrived almost simultaneously in the Early Middle Ages

Methods

Results

Conclusion