Haplogroup I-M438, also known as I2 (ISOGG 2019), is a human DNA Y-chromosome haplogroup, a subclade of haplogroup I-M170. Haplogroup I-M438 originated some time around 26,000–31,000 BCE. It originated in Europe and developed into several main subgroups : I2-M438*, I2a-L460, I2b-L415 and I2c-L596. The haplogroup can be found all over Europe and reaches its maximum frequency in the Dinaric Alps (Balkans) via founder effect. Examples of basal I-M438* have been found in males from Crete and Sicily .
Origin & prehistoric presence
Haplogroup I2a was the most frequent Y-DNA among western European mesolithic 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). Subclades of I2a1 (I-P37.2), namely I-M423 and I-M26 have been found in remains of Western European Hunter-Gatherers dating from 10,000 to 8,000 years before present respectively.
In a 2015 study published in Nature, the remains of six individuals from Motala ascribed to the Kongemose culture were successfully analyzed. With regards to Y-DNA, two individuals were ascribed to haplogroup I2a1b, one individual was ascribed to haplogroup I2a1, and one individual was ascribed to haplogroup I2c.
Subclades of I-L460
I-P37.2
The I-P37.2+, also known as I2a1a (ISOGG 2019) (The subclade divergence for I-P37.2 occurred 10.7±4.8 kya. The age of YSTR variation for the P37.2 subclade is 8.0±4.0 kya. It is the predominant version of I2 in Eastern Europe. The I2a is further made up by sub-groups I-M26, I-M423, I-L1286, I-L880.
I-L158
Haplogroup I-M26 (or M26) I2a1a1a (ISOGG 2019).
Haplogroup I-L158 (L158, L159.1/S169.1, M26) accounts for approximately 40% of all patrilines among the Sardinians. It is also found at low to moderate frequency among populations of the Pyrenees (9.5% in Bortzerriak, Navarra; 9.7% in Chazetania, Aragon; 8% in Val d'Aran, Catalunya; 2.9% in Alt Urgell, Catalunya; and 8.1% in Baixa Cerdanya, Catalunya) and Iberia, and it has been found in 1.6% of a sample of Albanians living in the Republic of North Macedonia and 1.2% (3/257) of a sample of Czechs. The age of YSTR variation for the M26 subclade has been calculated at 8.0±4.0 kya.
I-L178
I-L178 is very rare, but has been found in two persons from Germany and one from Poland. The age of YSTR variation for the M423 subclade is 8.8±3.6 kya.
I2a-L621
I2a1a2b-L621 is typical of the Slavic populations, being highest in Southeastern European regions of Bosnia-Herzegovina and South Croatia (>45%), in Bosniaks (43.53-52.17%), Croats (37.7-69.8%), and Serbs (36.6-42%), because of which is often called "Dinaric". It has the highest variance and also high concentration in Eastern Europe (Ukraine, Southeastern Poland, Belarus). According to YFull YTree it formed 11,400 YBP and had TMRCA 6,500 YBP, while its main subclades lineage is I-CTS10936 (6,500-5,600 YBP) > I-S19848 (5,600 YBP) > I-CTS4002 (5,600-5,100 YBP) > I-CTS10228 (5,100-3,400 YBP) > I-Y3120 (3,400-2,100 YBP) > I-Y18331 (2,100 YBP) / I-Z17855 (2,100-1650 YBP) / I-Y4460 (2,100 YBP) / I-S17250 (2,100-1,850 YBP) > I-PH908 (1,850-1,700 YBP).