— Ch. 1 · Defining Genetic Markers —
Haplogroup I-M253.
~4 min read · Ch. 1 of 6
The genetic identity of Haplogroup I-M253 rests on a specific set of single nucleotide polymorphisms. These markers include M253, M307.2/P203.2, and M450/S109 among others. A 2017 ISOGG report lists over thirty distinct mutations that define this lineage. Peter Underhill of Stanford University identified the primary marker M253. Michael Hammer from the University of Arizona contributed to defining P30. James F. Wilson at the University of Edinburgh helped establish P40. Each mutation represents a change in the DNA sequence at a precise location on chromosome Y. The C to T transition occurs at position ChrY:13532101 for the M253 marker. The G to A shift defines the P30 variant found in many carriers today.
Origins And Ancient History
Haplogroup I1 first appeared among Upper Paleolithic European hunter-gatherers as a minor lineage. It remained rare until the Nordic Bronze Age triggered its rapid expansion. Only six ancient DNA samples dated before the Nordic Bronze Age have been assigned to haplogroup I1. Sample SF11 comes from a Scandinavian hunter-gatherer buried on Stora Karlsö around 7500 BC. This individual carried nine of the 312 SNPs that define modern I1. Another sample BAB5 dates between 5600 and 4900 BC but lacks radiocarbon dating confirmation. Oll009 is an early Bronze Age man from Southern Sweden who lived between 1930 and 1750 BC. He possessed high Western Steppe-Herder ancestry similar to Battle Axe culture populations. Most living men with I1 share a common ancestor born between 2500 and 2400 BCE. This suggests a founder effect occurred during the Nordic Bronze Age rather than earlier periods.