Description
Haplogroup D1a (Z27276) is the dominant Y-DNA lineage of the Tibetan Plateau and surrounding Himalayan regions, found at very high frequencies among Tibetans, Bhutanese, Sherpa, and related Himalayan peoples. It is a defining genetic marker of the ancient populations that colonized and adapted to the high-altitude Tibetan Plateau — one of the most extreme environments ever inhabited by modern humans. D1a is essentially absent outside the Himalayan/Central Asian region, reflecting the remarkable genetic isolation of high-altitude Tibetan communities over tens of thousands of years.
Interesting Fact
Tibetans carrying D1a (and other Tibetan-specific lineages) show strong genetic signals of natural selection at the EPAS1 gene — the so-called 'superhero gene' — which allows them to thrive at altitudes above 4,000 meters by regulating hemoglobin production. This adaptation appears to have been acquired partly through ancient admixture with Denisovans, a distinct archaic human population.
Distribution by Ethnicity
| Ethnic distribution | Region | Frequency | Sample |
|---|---|---|---|
| Tibetans | Tibet / High Asia | n=400 | |
| Sherpa (Nepal) | Himalaya | n=150 | |
| Bhutanese | Himalaya | n=200 | |
| Ladakhi | India (Ladakh) | n=100 |
Tags
References
- Gayden et al. (2007) — The Himalayas as a directional barrier to gene flow. American Journal of Human Genetics 80(5), 884–894.