The Bulgarians are part of the Slavic ethnolinguistic group as a result of migrations of Slavic tribes to the region since the 6th century AD and the subsequent linguistic assimilation of other populations.Expansions: Competition and Conquest in Europe Since the Bronze Age, Reykjavíkur Akademían, 2010, , p. 194.
Hellenthal et al., 2014 estimated from data of 94 modern populations a couple of analyses on Bulgarians inferred from an admixture event in 1000-1600 YBP between a Slavic and a Cypriot donor group: to a Polish donor group Bulgarians are of an estimated 59% Polish-like and 41% Cypriot-like admixture; to a Belarusian, Bulgarians are of 46% Belarusian-like and 54% Cypriot-like admixture. Early gene flows between southeastern and eastern Europe make it difficult to obtain a correct estimate, although young enough identical by descent segments confirmed such connection and that the East and West Slavs share more identical by descent segments with South Slavs than with Greeks, inter-Slavic populations (a group of Romanians, Gagauz), but less with Balts, while the South Slavs share similar number with East and West Slavs, but fewer with Greeks.
The phenomenon of distinct genetic substrata in the West, East, and South Slavs would imply several mechanisms, including cultural assimilation of indigenous populations by bearers of Slavic languages as a major mechanism of the spread of Slavic languages to the Balkan Peninsula.Rebala et al. (2007) Y-STR variation among Slavs: evidence for the Slavic homeland in the middle Dnieper basin About 56% of the Bulgarian autosomal genetic ancestry is derived from Medieval Central and Eastern European populations, genetically related to present-day Eastern European populations, including Slavic-speaking populations. This substantial Medieval Central and Eastern European contribution reflects population movements and admixture into the Balkans during the Early Medieval period and represents the largest identifiable ancestral component in present-day Bulgarians as shown in the study conducted by Sarno et al., 2025 published in the American Journal of Biological Anthropology.
Around 4% of Bulgarian genes are derived outside of Europe and the Middle East or are of undetermined origin (by 858 CE), of which 2.3% are from Northeast Asia and correspond to Asian tribes such as Bulgars,Science, 14 February 2014, Vol. 343 no. 6172, p. 751, A Genetic Atlas of Human Admixture History, Garrett Hellenthal at al.: " CIs. for the admixture time(s) overlap but predate the Mongol empire, with estimates from 440 to 1080 CE (Fig.3.) In each population, one source group has at least some ancestry related to Northeast Asians, with ~2 to 4% of these groups total ancestry linking directly to East Asia. This signal might correspond to a small genetic legacy from invasions of peoples from the Asian steppes (e.g., the Huns, Magyars, and Bulgars) during the first millennium CE." a consistent very low frequency for Eastern Europe as far as Uralic-speaking Hungarians.
Y-DNA The national groups of Eastern Europe are characterized by dominant haplogroups R1a or I2, while those of Western Europe are characterized by dominant haplogroups R1b or I1, and by other dominant haplogroups in Europe are characterized Albanians, Finns, Greeks, and Turks, and over 50% of the total pool of each European nation other than the latter consists of these 4 haplogroups. A consistent pattern of both all national and regional groups of Bulgarians and Balto-Slavs is that their sum of haplogroups R1a and I2 is always larger than their sum of R1b and I1, while this ratio is vice versa in the Europeans not native to the Post-Eastern Bloc. Bulgarians, as some of their neighbours show the highest diversity of haplogroups in Europe, marked by significant (> 10%) frequencies of 5 major haplogroups. Most Bulgarians belong to three unrelated haplogroups, 20% of whom to I-M423 (I2a1b), 18% to E-V13 (E1b1b1a1b1a) and 17% to R-Z282 (R1a1ab1), but the biggest part belongs to macro-haplgoroup R (~28%). The major haplogroups, grouped by age of around 20 kya, are:Y-Chromosome Diversity in Modern Bulgarians: New Clues about Their Ancestry, Karachanak S, Grugni V, Fornarino S, Nesheva D, Al-Zahery N, et al. (2013) Retrieved Oct 2013.
Haplogroup I-L460 (I2a) is presented at levels 21.9% Karachanak 2013 according to 808 Bulgarian male samples of the largest-scale study from 2013. By higher levels are defined the profiles of Ukrainians and all South Slavs other than Slovenians.Varzari 2003 and 2007, Kushniarevich 2015, Noevski 2010, Marjanovic 2005, Mrsic 2012, Todorovic 2014, Vakar et al 2010 Evidence points to European origin for macro-haplogroup I, and Levantine for its immediate ancestor- IJ. Its exclusive and now patchy distribution within Europe suggested a very early entry in to Europe during Palaeolithic colonization, which was confirmed by the lack of its ancient DNA outside of the continent and ~13,000 years old European Cro-Magnon remains belonging to I2a. I2a2 is the most frequent haplogroup of European male remains dated to the Metal Ages, while I2a1 and I2a1b are most common in the Mesolithic. as such they were the primary haplogroups of pre-historic European hunter-gatherers. Initially a Holocene expansion of I2a in Southeastern Europe is supposed;Rootsi 2004 however Dinaric is descended by several 'only child' sublclades and it is suggested that its most recent common ancestor is aged only 2200 yearsyfull making it the youngest and most common micro-group.
I2a is recorded to be the dominant haplogroup in the former Sofia-city, Sofia, Plovdiv and Varna province between 23-33%, dropping under 10% in central Bulgaria. Bulgarian Hg I2a most often belongs specifically to the P37.2, M423 branch ("Hg I2a1b"), representing 20% of Bulgarian males, the rest ~2% of Bulgarian males belong to the subclade M223 (I2a2a).It makes up an absolute majority among the tallest populations. Many authors claim that the higher ratio of I2a1b over R1a that is observed in the Balkans today was present before the Slavic expansion, owed to indigenous tribes,Karmin M 2015Underhill 2014 while the most recent common ancestor of I-Y3120, to which all Bulgarian lines of I-P37 belong, is 2100 years old and challenges this suggestion. Although older research considered that the high frequency of this subclade in the South Slavic-speaking populations to be the result of "pre-Slavic" paleolithic settlement in the region, the research by O.M. Utevska (2017) confirmed that the haplogroup STR haplotypes have the highest diversity in Ukraine, with ancestral STR marker result "DYS448=20" comprising "Dnieper-Carpathian" cluster, while younger derived result "DYS448=19" comprising the "Balkan cluster" which is predominant among the South Slavs. This "Balkan cluster" also has the highest variance in Ukraine, which indicates that the very high frequency in the Western Balkan is because of a founder effect. Utevska calculated that the STR cluster divergence and its secondary expansion from the middle reaches of the Dnieper river or from Eastern Carpathians towards the Balkan peninsula happened approximately 2,860 ± 730 years ago, relating it to the times before Slavs, but much after the decline of the Cucuteni–Trypillia culture. More specifically, the "Balkan cluster" is represented by a single SNP, I-PH908, known as I2a1a2b1a1a1c in ISOGG phylogenetic tree (2019), and according to YFull YTree it formed and had TMRCA approximately 1,850-1,700 YBP (2nd-3rd century AD). Although it is dominant among the modern Slavic peoples on the territory of the former Balkan provinces of the Roman Empire, until now it was not found among the samples from the Roman period and is almost absent in contemporary population of Italy. It was found in the skeletal remains with artifacts, indicating leaders, of Hungarian conquerors of the Carpathian Basin from the 9th century, part of Western Eurasian-Slavic component of the Hungarians. According to Pamjav et al. (2019) and Fóthi et al. (2020), the distribution of ancestral subclades like of I-CTS10228 among contemporary carriers indicates a rapid expansion from Southeastern Poland, is mainly related to the Slavs and their medieval migration, and the "largest demographic explosion occurred in the Balkans".
Haplogroup E-V68 (E1b1b1a) is presented at levels 19.6% per 808 samples.(Karachanak 2013) The ultimate origin of E-V68 points to northeastern Africa, specifically near the Nile and Lake Alexandria.Cruciani 2004 Thus this haplogroup represents a more recent Bronze Age "out of Africa" movement into Europe via the Balkans. The macro-haplogroup E still prevails in most of the African continent, but through the long-term migrations the sub-Saharian maternal lineage Hg L was lost lacking completely in the Balkans. Holocene movement into the Near East is proposed, then several thousand years ago, a movement into the Balkans. All V68-positive Bulgarians belong to its M78 subclade, which is the prevailing haplogroup in most of northeast Africa and around the Balkans. The presently mostly European V13 (E1b1b1a1b1a) originated in western Asia according to the most plausible scenario and is presented at ~18% among Bulgarian males. Recent findings of V13 in a Neolithic context in Iberia (dated to ~ 7 kya) give a terminus ante quem.Lacan 2011 However, it might have really begun to expand in the Balkans somewhat later, perhaps during the population growth of the Bronze Age.Cruciani It resulted to be the dominant haplogroup in the former Burgas, Lovech, Montana and Razgrad province, from 20% to 38%. Like I-P37 above, it is rather limited to Europe but peaks in the Balkans, only for the Albanians, Greeks, Macedonians, various Romani, Montenegrins, Serbs and Romanians are recorded higher levels than Bulgarians.Sarno et al 2015, King et al 2008, Mirabal et al, Petricic et al 2005, Martinez-Cruz 2012 It has been detected on ancient Thracian remain from Bulgaria. An odd low frequency of Haplogroup E of 10% is recorded in the capital Sofia, which is the lowest on the Balkan Peninsula after Croatia and the same level is observed as far as Berlin.