Human genetic divergence as humans humans spread across the globe was sped up by mating with other related species. Genetic sequencing of extinct human relatives known as Denisovans has enabled comparison of Han, Tibetan and Denisovan DNA. This has led to discovery of DNA in Tibetans from Denisovans that adapts Tibetans to high altitude living,
Shenzhen, July 2, 2014---An international team, led by researchers from BGI and University of California, presented their latest significant finding that the altitude adaptation in Tibet might be caused by the introgression of DNA from extinct Denisovans or Denisovan-related individuals into humans. This work published online in Nature sheds new light into understanding human's adaptation to diverse environments including temperature extremes, new pathogens, and high altitude. Other important collaborators of this study include the scientists from The People's Hospital of Lhasa, South China University of Technology, among others.
The evolutionary adaptations has allowed Tibetans to have no trouble living at 13,000 feet all the year round.
The rest of us can't function as well at 13,000 feet. Women without the adaptations miscarry at a higher rate.
Human groups as they migrated across Eurasian and become separated for long periods of time developed genetic variants that adapted them to local conditions. But some humans got much more sophisticated adaptations from Denisovans who had been living in Asia for hundreds of thousands of years.
While Han Chinese and TIbetans have 0.2% Denisovan genes other groups in the Pacific islands have higher percentages of Denisovan genes. We do not yet know what adaptative advantages they gain from these Denisovan genes.
Steal genes from another species and then drive that species to extinction. Did humans do this?
"We have very clear evidence that this version of the gene came from Denisovans," a mysterious human relative that went extinct 40,000-50,000 years ago, around the same time as the more well-known Neanderthals, under pressure from modern humans, said principal author Rasmus Nielsen, UC Berkeley professor of integrative biology. "This shows very clearly and directly that humans evolved and adapted to new environments by getting their genes from another species."
Europeans similarly have some Neanderthal genes. We will also eventually learn what adaptive advantage they provide.
Will geneticists eventually uncover Denisovan genes that are not in any human population that would provide some perceived benefit to humans? Will we see humans adding some Denisovan or Neanderthal genes into embryos that they create to have children? Or will Denisovans or Neanderthals be cloned ad brought back to life?
|Share |||Randall Parker, 2014 July 04 09:49 PM|