Neanderthal DNA Purged From Our Genomes
Another Neanderthal extinction is taking place, and it's happening in our genomes, according to research that found natural selection is slowly removing Neanderthal genetic variants from modern populations. The study, published in PLOS Genetics, helps to explain what happened to all of those other Neanderthal genetic signatures that were more evident right after our species — known as anatomically modern humans, or AMH — mated with Neanderthals.
"So the first generation of hybrids would have been half Neanderthal and half AMH because they had one Neanderthal parent and one AMH parent," said senior author Graham Coop, a professor at UC Davis. "Later generations of hybrids may have more or less Neanderthal ancestry depending on whether they had more Neanderthal or AMH ancestors [for example, great grandparents]."
Neanderthal-Human Sex Happened Earlier Than Thought
A child conceived 100,000 years ago from a Neanderthal and modern human mating was announced in early 2016. The woman, from Siberia, was clearly a Neanderthal, but she retained DNA from our species. It's been known that people of European and Asian ancestry today possess a small amount of Neanderthal DNA in their genomes, but the Neanderthal woman offered the first evidence that gene flow from interbreeding went from modern humans into Neanderthals as well.
The study, published in the journal Nature, "is also the first to provide genetic evidence of modern humans outside Africa as early as 100,000 years ago," said Sergi Castellano, who co-led the research and is a scientist at the Max Planck Institute for Evolutionary Anthropology.
Neanderthals Could Have Domesticated Dogs
|Many of the earliest dogs resembled this modern Siberian husky.|
"Dogs were domesticated by hunter gatherers, prior to the advent of agriculture," Frantz said. "Dogs most likely provided multiple services to humans, such as facilitating hunting or providing protection."
The researchers can't yet rule out that Neanderthals or some other ancient human first domesticated dogs. Other research teams have found possible dog remains going back to the Neanderthal era.
Homo Erectus Walked Like a Man
Right-Handed Homo habilis
Co-author David Frayer of the University of Kansas explained that, among the network of deep striations found only on the lip face of the upper front teeth, most cut marks veered from left down to the right. Analysis of the marks makes it likely they came from when the individual used a tool with his right hand to cut food he was holding in his mouth while pulling with the left hand, he said in a press release. The scratches can be seen with the naked eye, but a microscope was used to further investigate them.
Neanderthal Diet: 80 Percent Meat, 20 Percent Fruit and Veg
"Previously, it was assumed that the Neanderthals utilized the same food sources as their animal neighbors," Bocherens said in a press release. "However, our results show that all predators occupy a very specific niche, preferring smaller prey as a rule, such as reindeer, wild horses or steppe bison, while the Neanderthals primarily specialized on the large plant-eaters such as mammoths and woolly rhinoceroses."
Neanderthals also ate fruits, vegetables and other plants, the researchers determined.
Clues to Hobbit Human Relatives and Disappearance
Aida Gómez-Robles, a scientist at George Washington University specializing in human evolution, told Seeker the research demonstrates "that the origin of Homo floresiensis is very old, which confirms that this is a totally valid species with old evolutionary roots."
We also learned that humans were on Hobbit turf at around the same time that Homo floresiensis seemingly disappeared from the face of the earth. The evidence is a pair of 46,000-year-old human teeth found in Flores' Liang Bua cave. Could our appearance and the Hobbits' disappearance just be a coincidence? The discovery would seem to implicate our species in whatever happened to the Hobbits.
Many People Today Could Be Part Denisovan
|Schoolchildren from Bhutan.|
"There are certain classes of genes that modern humans inherited from the archaic humans with whom they interbred, which may have helped the modern humans to adapt to the new environments in which they arrived," said senior author David Reich, a geneticist at Harvard Medical School. "On the flip side, there was negative selection to systematically remove ancestry that may have been problematic from modern humans. We can document this removal over the 40,000 years since these admixtures occurred."
In terms of helping modern humans, Denisovans are known to have given people from Tibet and nearby regions genetic adaptations for life at high altitudes.
Denisovans Gave Some People Cold Tolerance Too
He added, "The gene is also involved in a number of other traits, like body fat distribution, bone and facial morphology (structure)."
Read more at Discovery News