Population genetics is a scientific discipline which contributes to the examination of the human evolutionary and historical migrations. Particularly useful information is provided by the research of two uniparental markers within our genome, the Y-chromosome (Y-DNA) and mitochondrial DNA (mtDNA), as well as autosomal DNA. The data from Y-DNA and autosomal DNA suggests that the Serbs mostly are descendants of the early Slavs of the medieval migration period, according to mtDNA have genetic diversity which fits within a broader European maternal genetic landscape, and overall have a uniformity with other South Slavs from the territory of former Yugoslavia.
There are many Paleolithic period sites located in the territory of Serbia, mostly ascribed to the Mousterian phase in the Middle Paleolithic period. In the Neolithic period in Southeast Europe were founded major cultures like Vinča, Varna, Starčevo. In the Bronze Age happened symbiosis between Proto-Indo-Europeans of Kurgan culture and autochthonous populations, leading to the formation among others also of Proto-Illyrians. They gradually mixed and were assimilated by the Romans, Celts, Ostrogoths, and finally Early Slavs since the late 6th century.
Y-DNA Y-chromosomal haplogroups identified among the Serbs from Serbia and near countries are the following with respective percentages: I2a (36.6-42%), E1b1b (16.5-18.2%), R1a (14.9-15%), R1b (5-6%), I1 (1.5-7.6%), J2b (4.5-4.9%), J2a (4-4.5%), J1 (1-4.5%), G2a (1.5-5.8%), and several other uncommon haplogroups with lesser frequencies.
I2 is the most prevailing haplogroup, accounting for one-third of Serbians. According to 2019 study is represented by four sub-clusters I2-PH908 (25.08%), I2-L621 (7.59%), I2-CTS10228 (3.63%) and I2-M223 (0.33%), while according to detailed 2024 study of haplogroup I2-P37.2 was found to be predominantly represented by subclade I2-PH908 (62-79%, mostly subclades I-FT14506 and I-FT16449), followed by I2-Z17855, I2-L621, I2-Y4882, I2-Y4460, I2-CTS595, and I2-Y5595. A 2019 and 2025 study of Serb samples from different parts of the Western Balkans showed that "approximately half of them originated from Herzegovina and Old Herzegovina" which population throughout history strongly influenced today's Serbian male genetics. Older research considered that the high frequency of this subclade in the South Slavic-speaking populations to be the result of a "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 I-L621 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". Recent research also indicate that the haplogroup I2 in South Slavs is predominantly represented by subclades which came with Slavic migration from Eastern Europe.
E1b1b-M215 is the second most prevailing haplogroup amongst Serbs, accounting for nearly one-fifth of Serbians. It is represented by four sub-clusters E-V13 (17.49%), E1b1b-V22 (0.33%), and E1b1b-M123 (0.33%). In Southeast Europe, its frequency peaks at the southeastern edge of the region and its variance peaks in the region's southwest. Although its frequency is very high in Kosovar Albanians (46%) and Macedonian Romani (30%), this phenomenon is of a focal rather than a clinal nature, most likely being a consequence of genetic drift. E-V13 is also high amongst Albanians in North Macedonia (34%) and Albanians in Albania (24%), as well as ethnic Macedonians, Romanians, and Greeks. It is found at low to moderate frequencies in most Slavic populations. However, amongst South Slavs, it is quite common. It is found in 27% of Montenegrins, 22% of Macedonians, and 18% of Bulgarians, all Slavic peoples. Moderate frequencies of E-V13 are also found in Italy and western Anatolia. In most of Central Europe (Hungary, Austria, Switzerland, Ukraine, Slovakia), it is found at low to moderate frequencies of 7-10%, in both R1a (Slavic) and R1b (Germanic/Celtic) dominated populations. It likely originated in the Balkans, Greece, or the Carpathian Basin 9000 YBP or shortly before its arrival in Europe during the Neolithic. Its ancestral haplogroup, E1b1b1a-M78, is of northeast African origin.
R1a1-M17 accounts for about one-seventh to one-sixth of Serbian Y-chromosomes. It is represented by four sub-clusters R1a (10.89%), R1a-M458 (2.31%), R1a-YP4278 (1.32%), and R1a-Y2613 (0.33%). Its frequency peaks in Ukraine (54.0%). It is the most predominant haplogroup in the general Slavic paternal gene pool. The variance of R1a1 in the Balkans might have been enhanced by infiltrations of Indo-European speaking peoples between 2000 and 1000 BC, and by the Slavic migrations to the region in the early Middle Ages. A descendant lineage of R1a1-M17, R1a1a7-M458, has the highest frequency in Central and Southern Poland.
R1b1b2-M269 is moderately represented among Serbian males (6–10%), 10% in Serbia (Balaresque et al. 2010), with subclade M269* (xL23) 4.4% in Serbia, 5.1% in Macedonia, 7.9% in Kosovo. The highest frequency in the central Balkans (Myres et al. 2010). It has its frequency peak in Western Europe (90% in Wales), but a high frequency is also found in Central Europe among the West Slavs (Poles, Czechs, Slovaks) and Hungarians as well as in the Caucasus among the Ossetians (43%). It was introduced to Europe during the bronze age by incomers from the Eurasian Steppe, along with Indo-European languages. Serb bearers of this haplogroup are in the same cluster as Central and East European ones, as indicated by the frequency distributions of its sub-haplogroups with respect to total R-M269. The other two clusters comprise, respectively, West Europeans and a group of populations from Greece, Turkey, the Caucasus and the Circum-Uralic region.
J2b-M102 and J2a1b1-M92 have low frequencies among the Serbs (6–9% combined). Various other lineages of haplogroup J2-M172 are found throughout the Balkans, all with low frequencies. Haplogroup J and all its descendants originated in the Middle East. It is proposed that the Balkan Mesolithic foragers, bearers of I-P37.2 and E-V13, adopted farming from the initial J2 agriculturalists who colonized the region about 7000 to 8000 YBP, transmitting the Neolithic cultural package.
I1-M253 is also found in low frequencies (1.5-7.6%) and is represented by three sub-clusters I1-P109 (5.28%), I1 (1.32%), and I1-Z63 (0.99%).
An analysis of molecular variance based on Y-chromosomal STRs showed that Slavs can be divided into two groups: one encompassing West Slavs, East Slavs, Slovenes, and western Croats, and the other – all remaining Southern Slavs. Croats from northern Croatia (Zagreb region) fell into the second group. This distinction could be explained by a genetic contribution of pre-Slavic Balkan populations to the genetic heritage of some South Slavs belonging to the group. Principal component analysis of Y-chromosomal haplogroup frequencies among the three ethnic groups in Bosnia and Herzegovina (Bosnian Serbs, Bosnian Croats, and Bosniaks), showed that Bosnian Serbs and Bosniaks are genetically closer to each other than either of them is to Bosnian Croats (mainly due to Bosnian Croats very high I2a frequency). According to correspondence analysis, admixture analysis and Rst genetic distance, Serbian regional population samples cluster together and are closest to Montenegrins, Macedonians and Bulgarians, with Western Serbians being an intermediate between them and Croatian-Bosnian and Herzegovinian cluster. According to 2022 study on 1200 samples from Serbia, Old Herzegovina, Kosovo and Metohija, "genetic distances between three groups of samples, evaluated by the Fst and Rst statistical values, and further visualized through multidimensional scaling plot, showed great genetic similarity between datasets from Old Herzegovina and present-day Serbia. Genetic difference in the haplogroup distribution and frequency between datasets from historical region of Old Herzegovina and from geographical region of Kosovo and Metohija was confirmed with highest Fst and Rst values".
Y-DNA Haplogroup frequencies