Disease in people today were picked up through interbreeding with Neanderthals:
Genome studies reveal that our species (Homo sapiens) mated with Neanderthals after leaving Africa.
But what was clear before this Neanderthal DNA did and if there was any impact on human health .
When Neanderthals and modern humans met and mixed , they were on the very edge of being compatible biological ”
Harvard Medical School Prof David Reich
Between 2% and 4% of the genetic fingerprint of non-Africans today came from Neanderthals.
By screening the genomes of 1,004 modern humans, Sriram Sankararaman and colleagues identified the regions that carry different versions of Neanderthal genes.
Genetic variant associated with a difficulty in quitting should be found to have a Neanderthal origin is a surprise.
There is no suggestion of our evolutionary cousins were smoking in their caves.
Instead, the researchers argue , this mutation may have more than one function , so the modern effect of this marker in smoking behavior may be one of the impacts it has among many.
The researchers found that the DNA Neanderthal not evenly distributed throughout the human genome , rather than being commonly found in the regions that affect the skin and hair .
This suggests some variants of the gene provided a quick way to modern to suit the new cooler environments they encountered as they moved in Eurasia humans. When populations were found , Neanderthals had already been adapted to these conditions for several hundred thousand years.
Chubby Chasers once covered the gamut from Britain to Siberia, but became extinct about 30,000 years ago, as Homo sapiens was spreading from an African country.
Neanderthal ancestry was found in regions of the genome associated with the regulation of skin pigmentation .
I think what we’re seeing in many ways they are the dying remains of this extinct genome as slowly purged human populations ”
Joshua Akey University of Washington
“We found evidence that genes of skin Neanderthals did Europeans and East Asians more evolutionarily fit,” said Benjamin Vernot , University of Washington, co -author of a separate study in Science magazine .
The genes of keratin filaments , a fibrous protein that lends itself to the hardness of the skin, hair and nails, also enriched with Neanderthal DNA . This may have helped provide newcomers with thicker insulation against the cold, the scientists suggest .
“It is tempting to think that Neanderthals already adapted to the environment does not always lead African and genetics ( modern) humans,” said Professor David Reich of Harvard Medical School , co-author of the Nature paper .
But other gene variants influence human diseases , such as type 2 diabetes, long-term depression , lupus, biliary cirrhosis – an autoimmune liver disease – Crohn ‘s disease and . For Crohn ‘s disease , Neanderthals passed on markers that increase and decrease the risk of disease .
Asked whether our ancient relatives actually suffering from these diseases as well, or whether mutations in question only affected the risk of disease when transplanted to a modern human gene pool , Mr. Sankararaman said : “We have a fine knowledge of genetics the Neanderthals to answer this , “but added that further study of their genomes may she light on this issue.
Joshua Akey , University of Washington, one of the authors of the journal Science , added: “Mixture happened relatively recently in evolutionary terms , so you can not expect the entire Neanderthal DNA have been swept away by this point.
“I think what we’re seeing in many ways they are the dying remains of this extinct genome as slowly purged of the human population . ”
However, some regions of the genome were found to be devoid of Neanderthal DNA , suggesting that certain genes had such adverse effects in the offspring of matings by modern Neanderthal that indeed have been emptied and actively quickly through natural selection .
“We found that there are large regions of the genome where most modern humans have little or no Neanderthal ancestry. ”
“This reduction of Neanderthal ancestry was probably due to selection against genes that were wrong – harmful – . For us ”
Neanderthal deficient regions include genes that are specifically expressed in the testes and in the X ( female ) chromosome .
This suggests that some human hybrids – modern Neanderthals had reduced fertility and in some cases were sterile.
” We are told that when Neanderthals and modern humans met and mixed , they were on the verge of being biologically compatible” said Professor Reich.
Another region of the genome includes genes neanderthales lacked a gene called FOXP2 , which is believed to play an important role in human speech .
Joshua Akey said his team’s findings were consistent with that there have been multiple pulses cross between modern humans and Neanderthals .