Scientists Suspected About Human's Extinct Ancestors Who Has Reached 'The Roof Of The World' Earlier Than Homo Sapiens

Update: 2021-12-14 14:30 IST

Pic Courtesy: Getty Images

Some scholars believe that our species would never have built its home on the world's highest and largest plateau if it hadn't been for an extinct relative of contemporary humans known as the Denisovans. Because it is 4,000 meters (13,000 feet) above sea level, the Tibetan Plateau, also known as the Himalayan Plateau, is known as the roof of the globe.

This enormous swath of elevated territory, which includes portions of Tibet, China, India, Pakistan, and several other nations in the region, is generally regarded as one of the final places where Homo sapiens permanently settled. According to studies, various relatives may have occupied the area throughout the last 160,000 years, but gaps in the record are difficult to understand.

A geneticist and an archaeologist have now proposed a different timeline that fits in with the minimal information they have. The researchers used archaeological and genetic evidence to create two distinct models of occupation: one that is continuous and the other that is fragmented over time. The two models can also be examined, which could one day tell researchers how far back modern populations go.

In the discontinuous scenario, humans came and went for thousands of years before settling down around 9,000 years ago. Recent evidence, on the other hand, could support the sustained settlement of the plateau between 30,000 and 40,000 years ago. If that's the case, the extended genetic history may have passed down some useful tips for surviving in thin air.

Recent DNA tests suggest that a single crossbreeding event between Denisovans and H. sapiens in East Asia, no more than 46,000 years ago, may have infused our species with the genes needed to thrive in such a low-oxygen environment.

Anthropologist Nicolas Zwyns of the University of California, Davis said that the transmission of some of their genes to us [might] be the game changer thousands of years later for our species to get adapted to hypoxia although they don't know if [Denisovans] were adapted to high altitude. Denisovans initially appeared on the Tibetan plateau around 160,000 years ago, as per archaeological data. However, it is still unknown if these early humans lived here all year or only came here on occasion.

The same can be said about our own species. The earliest archaeological evidence of H. sapiens on the plateau dates back 40,000 years, but continuous settlement is unlikely to have happened until after the last glacial period, around 11,000 years ago.

Given substantial gaps in the archaeological period, we'll probably only be able to figure out the truth if we include genetic data as well. Several modern Tibetans have DNA with a specific variant in the Endothelial Pas1 (EPAS1) gene, which increases oxygen transport in the blood and helps people endure the lack of oxygen observed at high elevations.

A Denisovan finger bone discovered in the mountains north of the Tibetan plateau in 2010 revealed a similar genetic anomaly. Perhaps, it is estimated that simply don't have enough Denisovan remains to make a definitive statement.

A recent genetic study has revealed that all East Asians, including Tibetans, have the same Denisovan DNA patterns, according to the authors of the current paper. This shows that genes from across the region were generated from a single interbreeding event that happened between 46,000 and 48,000 years ago and was unique to East Asians.

However, after this intermixing did H. sapiens reach the summit of the planet, presumably due to genes acquired from Denisovans in the lowlands.

According to research on the EPAS1 gene haplotype in current Tibetans, the peculiarity was positively selected between 2,800 and 18,300 years ago. Furthermore, the genetic split between current Tibetans and Han Chinese appears to have occurred 30,000 years ago, suggesting earlier selection.The authors of the new research say that until we know more, we shouldn't rule out the idea that H. sapiens lived permanently on the Tibetan Plateau as long as 40,000 years ago.

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