Y-DNA haplogroup I2a1 is most commonly found in the western Balkans, Romania, and Sardinia. It is also present in other European countries. Its maximum frequencies are observed in Bosnia (50%), Sardinia (39%), Croatia (37%), Serbia (32%), Montenegro (30%), Romania (28%), Moldova (21%), Macedonia (23%), Slovenia (20%), Ukraine (20%), Bulgaria (20%), Belarus (17%), Hungary (16%), Slovakia (16%), Albania (12%) and Greece (10%).
Haplogroup I2a1b-L621, particularly its subclade CTS10228, is often considered as another “Slavic” haplogroup (beside R1a), which is wrong and scientifically inadmissible. Haplogroups are a genetic, and not a geographical, linguistic, national, or social category. This means that they cannot be designated according to the language their carriers speak, the country they live in, or religion they practice... Each haplogroup denotes a common genetic origin of the people who share it, and they all belong to the same ethno-racial group which has had its own evolution.
In some cases, haplogroups are easily associated with certain ethno-racial/genetic groups. For example, it is obvious that most of today’s European R1a people (i.e. 99%) are the Slavs, the R1b people are the Celts (or, to be precise: not all R1b men are the Celts, but all Celts are R1b!!), and I1a people are the “Northmen” or Germans in general. Of course, the ancestors of these people were not known by those names 3000 years ago, but they, nevertheless, inherited the same Y-DNA lineages which genetic/ethno-racial Slavs, Celts, and Northmen/Germans inherit today.
Unfortunately, even though the haplogroup I2a is believed to have been the haplogroup of the first anatomically modern humans to inhabit Europe, Cro-Magnons, there is no single common name for all I2a people now. However, "I2a1 people" still represent a separate, distinct ethno-racial group, and they have always been (and will be) "I2a1 people", regardless of the subclade, or nation they belong to, time flow, migrations of their ancestors, place they live in, or the language they speak.
Nations are mixtures of different haplogroups, but haplogroups themselves do not mix. Therefore, not a single I2a1 man participated in the ethnogenesis of the genetic Slavs, but many I2a1 people definitely participated in the ethnogenesis of Slavic (or Germanic, Romance…) speaking nations.
According to data collected from an extensive research that has been conducted in the last dozen years, and a number of ancient and modern DNA test results from different European countries, it seems that the haplogroup I2a-L621 appeared somewhere along the Danube river about 12.000 years ago. The carriers of its oldest lineages have managed to survive until today in central-western Europe. (https://www.yfull.com/tree/I-L621/) It also seems that the subclade CTS10228 was formed in the same region more than 5000 years ago – most probably in today’s Germany, or France. The immediate descendant of CTS10228, Y3120 branch (which was presumably formed 3800 years ago) may have been born there too, but there is little evidence which could support this assumption. At present, it is only confirmed that the “Y3120 men” negative for downstream branches live in Poland, Germany, and the Balkans (Serbia, Croatia), and there are some Montenegrins... who are yet to be verified.
The initial lack of knowledge and information was confusing and it produced several contradicted theories about the place of the origin of Y3120 and, particularly, its subclades: Y4460, Y18331, S17250, and Z17855. The debate was mostly futile, and many arguments and premises proved to be insignificant, or simply wrong. Namely, the attention was focused on the issues such as haplogroup frequency, the number of representatives, haplotype diversity, archaeological learning of the distant past…, but it turned out that these parameters were unreliable “tools” in locating the area where Y3120 subclades originated, and they were of little help in explaining their development. However, in the last few years, thanks to BY and SNP test results, the picture has become clearer, and it became obvious that genetics and history complemented each other. Here are some raw facts:
- The carriers of Y3120 subclades live all over south-eastern and north-eastern/north-western Europe. But, the south-eastern Europe (from Croatia to Greece and Bulgaria) is the only region where all I-CTS10228 subclades (from Y3120 downwards) are grouped together – it undoubtedly points to a spatial and temporal continuity of some 2300-3800 years. It is even more significant that the primary lineages of all four Y3120 subclades are found exclusively in the (south-eastern) Balkans.
- The subclade Y4460 has many representatives in the northern Europe, and very few in the eastern Balkans. Some of the Y4460 people in Ukraine, Belarus, Poland… are positive for the oldest branches of this subclade, and all Y4460 people in Montenegro (e.g. members of the Kočan family), Greece, Bulgaria… carry the oldest lineages. None of the younger branches (from Y3106 downwards), which represent the majority in eastern and western Slavic countries, can be found in the Balkans! This could mean that:
a) Y4460 actually came to Balkan +2000 years ago (from the north), remained sparse, and for some reason did not evolve further – which is, when everything is considered, highly unlikely;
b) the greater part of Y4460 “clan” left the (eastern) Balkans +2000 years ago, crossed the Carpathian mountains and prospered in the Slavic and Baltic countries.
In either case, this is the crucial piece of information: there was no subsequent migration (in the 6th, 7th, or later centuries) to the Balkans which could have brought the younger branches.
- The oldest lineages of Y18331 are found in Greece, and all others are scattered mainly across the northern and eastern Europe. It is obvious where this Y3120 branch originated.
- The subclade S17250 was, according to the available data /yfull.com/tree/I-L621, I2a FTDNA project, and various national DNA projects/, undoubtedly formed in the Balkans, but something indeed extraordinary happened 2300-1850 years ago. As it is supposed, this is when the sub-branches PH908 and Y4882 appeared. And, for now, it appears that PH908 (which is, by the way, older) was born in the western Balkan, and Y4882 in central Europe.
a) The following facts indicate that that Y4882 originated in the north-west: the primary lineages are there; in the south-eastern Europe it is mainly represented with two younger branches, and the percentage varies from 0 to 1.5% (of all haplogroups). These people could have come to the Balkans with the Germans, or Slavs, but also independently, and more recently (because of their small number). Historically, the appearance of Y4882 and other central European S17250 branches (Y5596) can be connected with the Roman expeditions in Germania before and at the beginning of the Common Era – some S17250 men from Illyricum were definitely deployed there.
b) It is quite the opposite with PH908 – the primary (and other) lineages are in the western Balkans (and Italy); it represents the vast majority of I2a1 population in Croatia, Bosnia, Serbia, and Montenegro; and almost all north-European (Ukrainian, Russian…) PH908 men belong to younger sub-branches. This is the only CTS10228-Y3120 subclade which should be called “Dinaric”.
There are two historical realities which support the Balkan origin hypothesis of PH908.
1) A few people in Europe know that Montenegro (a small country in the western Balkan) is still a tribal society – people still consider themselves as members of different clans which, in most cases, originated from one man. In the late medieval times (13-15th century), Montenegrin tribes were designated as "Arbanases" and "Vlachs" by various (predominantly Serbian) rulers, notaries, and historians. Until the arrival of Turks (the second half of 15th century), the Arbanases and, more importantly, Vlachs /Vlahs/ were, without exception, differentiated from the Serbs, Croats, or Slavs in general. And, it is established that the medieval Vlachs were descendants of Romanized, pre-Slavic Balkan inhabitants. Recent DNA testing discovered that major Arbanas tribes in Montenegro belong to haplogroup E-V13, and major Vlach tribes to I2a S17250-PH908.
2) The presence of PH908 in the central and eastern European countries is the consequence of several well-documented migration waves which began with the Turkish conquest of the Balkans. Namely, it is estimated that more than 700.000 people left south-eastern Europe (at least 400.000 of them were from Serbia alone) and settled in Hungarian and Russian empires in the 15th, 17th, and 18th century. Approximately 30-40% of the men belonged to haplogroup I2a1b and it is safe to say that 75-80% of them carried PH908. This relocation process continued in the 19th century as well and involved thousands of people from Montenegro, Herzegovina, Croatia… It is estimated that the number of their living descendants outside the Balkan peninsula is +4.000.000.
- The Z17855 subclade was also formed in the eastern Balkan and it seems that its expansion (together with the expansion of E-V13 lineages) towards the north started in the 8th century when the Vlachs crossed the Danube and attacked the residing Slavs. With the arrival of Hungarians these Vlachs spread over a wider area. Another significant migration happened at the end of 15th century. Hence, we have Laccy Gorale, Wallasi in southern Poland (where the frequency of I2a1 haplogroup is the highest), and Moravian Wallachia in the Czech republic.
The genetic connection of the I2a1 men from the Carpathian mountains in Ukraine and the I2a1 Romanians and Moldavians was well documented in the study Populations of Transcarpathia and Bukovina on the genetic landscape of surrounding regions.
Scientific studies for additional reading:
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.00... Uniparental Genetic Heritage of Belarusians: Encounter of Rare Middle Eastern Matrilineages with a Central European Mitochondrial DNA Pool
https://medicine.dp.ua/index.php/med/article/view/257 Populations of Transcarpathia and Bukovina on the genetic landscape of surrounding regions (PDF in Russian)
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