Any news on Denisovans always attracts my attention. It is because I suspect them to be the inhabitants of Deva territory in a remote past. According to researchers Denisovans were short and they became extinct some 40,000 years ago. There are traces of their genes in Australians and Melanesians. This made them think that they were in the southern hemisphere in south-east parts of the globe. But the same gene imprints were found in the human remnants in Siberia, in Altai. This brings in the theory that they had moved from south to north or from north to south. The Wikipedia article on Denisovans has the following map showing the movement or spread of Denisovans in green colour.
Their period ended by 40,000 years before present. What strikes me in the current study is that a part of their gene is found in most Tibetans and that gene was found to be helping them to endure life in high altitudes where oxygen level is low. This makes me think whether Denisovans were also tuned to living in high altitudes. So far their presence in traces is found in people in Southeast Asia near the oceans. If they were supposed to have possessed a unique gene suitable for living in high altitudes, then it means their major habitat for many thousands of years must have been in high and cold regions.
This makes the mountains of Siberia as the perfect places for their natural habitat. This is where Uttarkuru was located according to Hindu texts and this is where Devas were supposed to have lived. Let me reproduce a map with Uttar Kuru from my old article 24,000 year old remains of the Malta boy – connected to Indian gene pool?
Further details of my views of the people of Uttarkuru based on Hindu texts can be read here: Discovery of 30,000 year human imprint in Siberia, the land identified as Uttarkuru.
There are references of mix –up of Devas with others in the past. For example, Muruga aka Karthikeya, of the Tamil lands – presumably in deep down the south near Australia at the time of 1st Sangam, around 12,500 years ago married Devyani of the Deva territory.
Earlier Matali, the charioteer of Indra (there may have been many Indras as that seems to be the title of the king of Devas) came down to Southern hemisphere in search of a groom for his daughter. There is yet another instance narrated in Mahabharata of a girl from Southern hemisphere marrying a person from Deva territory. Thus mix-up of people – seemingly with Denisovnas had happened. (Some Denisovans must have lived until 7000 years ago if my theorising of equating Denisovans with Devas is correct. The last time we hear about Devas was when Indrajit, son of Ravana over powered Indra.)
In this backdrop, the news about a Denisovan gene called as super- athlete gene being present in Tibetans that make them survive in low oxygen and generate more haemoglobin make me think that Denisovan habitat must have been in cold and high altitudes. The displacement of people from Altai to Vietnam via China which was allegorically explained in Anusasana parva – chapter 93) was perhaps the last time people from there shifted to south owing to climatic conditions. It is probable a branch of them shifted to Tibetan heights owing to the similarity in earlier habitat but lost forever later, leaving some imprints through mix-up.
Others who shifted towards south could not have survived owing to sea level habitat.
Waiting for more research results on Denisovans.
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From
Tibetans Inherit Super-Athlete Gene from Denisovans
Tibetans were able to adapt to high altitudes thanks to what is sometimes called the super-athlete gene, or more prosaically, EPAS1, they acquired when their ancestors bred with Denisovans – a mysterious group of prehistoric hominins that went extinct around 45,000 years ago.
Genetic researchers have found that part of the EPAS1 gene in Tibetans is almost identical to the gene in Denisovans. Image credit: Mauro Cutrona.
EPAS1 is activated when oxygen levels in the blood drop, triggering production of more hemoglobin. This gene has been referred to as the super-athlete gene because at low elevations, some variants of it help athletes quickly boost hemoglobin and thus the oxygen-carrying capacity of their blood, upping endurance.
An unusual variant of EPAS1 became widespread in Tibetans after they moved onto the high-altitude plateau several thousand years ago. This variant allowed them to survive despite low oxygen levels at elevations of 4,500 meters or more.
"We have very clear evidence that this version of the gene came from Denisovans. This shows very clearly and directly that humans evolved and adapted to new environments by getting their genes from another species," said Prof Rasmus Nielsen of the University of California, Berkeley, who is the senior author of a paper published in the journal Nature.
For their study, Prof Nielsen' team sequenced the EPAS1 gene in 40 Tibetans and 40 Han Chinese individuals.
The data revealed that the high-altitude variant of EPAS1 is so unusual that it could only have come from Denisovans. Aside from its low frequency in Han Chinese, it occurs in no other known humans, not even Melanesians whose genomes are nearly 5 percent Denisovan.
The variant (or allele) of EPAS1 found in Tibetans raises hemoglobin and red blood cell levels only slightly at high elevations, avoiding the side effects seen in most people who relocate to elevations above 4,000 meters.
"We found that part of the EPAS1 gene in Tibetans is almost identical to the gene in Denisovans and very different from all other humans. We can do a statistical analysis to show that this must have come from Denisovans. There is no other way of explaining the data," Prof Nielsen said.
Prof Nielsen described a possible scenario leading to this result: "modern humans coming out of Africa interbred with Denisovan populations in Eurasia as they passed through that area into China, and their descendants still retain a small percentage – perhaps 0.1 percent – of Denisovan DNA."
"The group that invaded China eventually split, with one population moving into Tibet and the other, now known as Han Chinese, dominating the lower elevations."
Prof Nielsen added: "there might be many other species from which we also got DNA, but we don't know because we don't have the genomes."
"The only reason we can say that this bit of DNA is Denisovan is because of this lucky accident of sequencing DNA from a little bone found in a cave in Siberia. We found the Denisovan species at the DNA level, but how many other species are out there that we haven't sequenced?"
Emilia Huerta-Sánchez et al. Altitude adaptation in Tibetans caused by introgression of Denisovan-like DNA. Nature, published online July 02, 2014; doi: 10.1038/nature13408
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From
Extinct human cousin gave Tibetans advantage at high elevation
Tibetans were able to adapt to high altitudes thanks to a gene picked up when their ancestors mated with a species of human they helped push to extinction, according to a new report by University of California, Berkeley, scientists. Extinct human cousin gave Tibetans advantage at high elevation
Tibetans were able to adapt to high altitudes thanks to a gene picked up when their ancestors mated with a species of human they helped push to extinction, according to a new report by University of California, Berkeley, scientists. Extinct human cousin gave Tibetans advantage at high elevation
A Chinese researcher collects a blood sample from an ethnic Tibetan man participating in the DNA study [Credit: Beijing Genomics Institute]
An unusual variant of a gene involved in regulating the body's production of hemoglobin -- the molecule that carries oxygen in the blood -- became widespread in Tibetans after they moved onto the high-altitude plateau several thousand years ago. This variant allowed them to survive despite low oxygen levels at elevations of 15,000 feet or more, whereas most people develop thick blood at high altitudes, leading to cardiovascular problems. "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." This is the first time a gene from another species of human has been shown unequivocally to have helped modern humans adapt to their environment, he said. Nielsen and his colleagues at BGI-Shenzhen in China will report their findings online July 2 in advance of publication in the journal Nature.
The gene, called EPAS1, is activated when oxygen levels in the blood drop, triggering production of more hemoglobin. The gene has been referred to as the superathlete gene because at low elevations, some variants of it help athletes quickly boost hemoglobin and thus the oxygen-carrying capacity of their blood, upping endurance. At high altitude, however, the common variants of the gene boost hemoglobin and its carrier, red blood cells, too much, increasing the thickness of the blood and leading to hypertension and heart attacks as well as low-birth-weight babies and increased infant mortality. The variant or allele found in Tibetans raises hemoglobin and red blood cell levels only slightly at high elevation, avoiding the side-effects seen in most people who relocate to elevations above 13,000 feet.
"We found part of the EPAS1 gene in Tibetans is almost identical to the gene in Denisovans and very different from all other humans," Nielsen said. "We can do a statistical analysis to show that this must have come from Denisovans. There is no other way of explaining the data." Harsh conditions on Tibetan plateau The researchers first reported the prevalence of a high-altitude version of EPAS1 in Tibetans in 2010, based on sequencing of the genomes of numerous Han Chinese and Tibetans.
Nielsen and his colleagues argued that this was the result of natural selection to adapt to about 40 percent lower oxygen levels on the Tibetan plateau. That is, people without the variant died before reproducing at a much higher rate than those with it. About 87 percent of Tibetans now have the high-altitude version, compared to only 9 percent of Han Chinese, who have the same common ancestor as Tibetans. Nielsen and his colleagues subsequently sequenced the EPAS1 gene in an additional 40 Tibetans and 40 Han Chinese. The data revealed that the high-altitude variant of EPAS1 is so unusual that it could only have come from Denisovans. Aside from its low frequency in Han Chinese, it occurs in no other known humans, not even Melanesians, whose genomes are nearly 5 percent Denisovan.
A high quality sequence of the Denisovan genome was published in 2012. Nielsen sketched out a possible scenario leading to this result: modern humans coming out of Africa interbred with Denisovan populations in Eurasia as they passed through that area into China, and their descendants still retain a small percentage -- perhaps 0.1 percent -- Denisovan DNA. The group that invaded China eventually split, with one population moving into Tibet and the other, now known as Han Chinese, dominating the lower elevations. He and his colleagues are analyzing other genomes to pin down the time of Denisovan interbreeding, which probably happened over a rather short period of time. "There might be many other species from which we also got DNA, but we don't know because we don't have the genomes," Nielsen said.
"The only reason we can say that this bit of DNA is Denisovan is because of this lucky accident of sequencing DNA from a little bone found in a cave in Siberia. We found the Denisovan species at the DNA level, but how many other species are out there that we haven't sequenced?" Author: Robert Sanders | Source: University of California - Berkeley [July 02, 2014]
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