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