Haplogroup I-M438
[4] Haplogroup I2a was the most frequent Y-DNA among Mesolithic Western European hunter-gatherers (WHG) belonging to Villabruna Cluster.
A 2015 study found haplogroup I2a in 13,500 year old remains from the Azilian culture (from Grotte du Bichon, modern Switzerland).
[1] I2a1a2b-L621 is typical of the Slavic populations, being highest in Southeastern European regions of Bosnia-Herzegovina and South Croatia (>45%),[3][13][14] in Croats (37.7-69.8%), Bosniaks (43.53-52.17%), and Serbs (36.6-42%)—often called "Dinaric".
[17] 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.
Peričić et al. (2005) for instance placed its expansion to have occurred "not earlier than the YD to Holocene transition and not later than the early Neolithic".
Utevska (2017), in her PhD thesis, despite being a part of research team who came to a different conclusion in 2015,[25] proposed 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.
[16] 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.
[16] However, STR-based calculations give overestimated dates,[26][27] and 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).
[40] Haplogroup I-M223 has been found in over 4% of the population only in Germany, the Netherlands, Belgium, Denmark, Scotland, and England (excluding Cornwall) – also the southern tips of Sweden and Norway in Northwest Europe; the provinces of Normandy, Maine, Anjou, and Perche in northwestern France; the province of Provence in southeastern France; the regions of Tuscany, Umbria, and Latium in Italy; Moldavia and the area around Russia's Ryazan Oblast and Mordovia in Eastern Europe.
Haplogroup I2a1b1a1a (ISOGG 2019) or I-M284, has been found almost exclusively amongst the populations of the United Kingdom and Ireland suggesting that it may have arisen amongst the Ancient Britons, with a most recent common ancestor (MRCA) who lived about 3,100 years BP.
[41] The presence of this subclade "provides some tentative evidence of ancient flow with eastern areas that could support the idea that the [late Celtic] La Tene culture was accompanied by some migration.
"[42] Where it is found in those of predominately Irish descent, with Gaelic surnames, it may suggest an ancestor who arrived in Ireland during prehistory, from Celtic Britain.
Found in Central Europe from Germany, Austria to Poland, Romania and Ukraine, but also in lower frequencies in Greece, Italy, France, Spain, England, Ireland, and Armenia.
