DENISOVANS LIVED IN TIBETAN PLATEAU, FOSSIL EVIDENCE SHOWS
02, May 2019
Prelims level : Environment Mains level : Technology, Economic Development, Bio diversity, Environment, Security and Disaster Management
Why in News
- Species adapted to low-oxygen environment before modern humans arrived
- Analysis of a fossil jawbone containing molars recovered from Baishiya Karst cave in Xiahe, Gansu, China shows Denisovans lived in the Tibetan Plateau some 1,60,000 years ago.
- The first evidence for Denisovans or Denisova hominins was first discovered in 2008 in a cave in the Altai mountains in Siberia.
- This is the first time evidence of Denisovan presence has been found outside the Denisova cave. Contrary to popular belief that high altitude regions were inhabited only by modern humans dating back to less than 40,000 years, the fossil remains conclusively prove that Denisovans lived in the Tibetan Plateau at an altitude of 3,280 metres much earlier — 1,60,000 years ago.
- The Denisova cave in Siberia is at an altitude of just 700 metres.
- Previous genetic studies have found that modern humans living in the Tibetan Plateau carried a special gene variant — EPAS1 (Endothelial PAS Domain Protein 1) — that allowed them to cope with low oxygen (hypoxia) environments typical of high altitude.
- This gene variant has been found in Denisovans
- The possible explanation for the presence of this gene variant in the hominin is that Denisovans lived for a long time in the plateau leading to the gene mutation. This mutation has later been passed on to modern humans.
- The carbonate matrix adhering to the sample was dated using Uranium-Thorium and the age was determined to be 1,60,000 years.
- Protein analysis shows that the Xiahe mandible belonged to a hominin population that was closely related to the Denisovans from Denisova Cave,”
- The Denisovans or Denisova hominins are an extinct species or subspecies of archaic humans in the genus Homo.