The ancient Neanderthals and Denisovans haven’t quite been erased from human history — their DNA lives on in modern humans, a new study has found.
A team of scientists at Harvard Medical School and UCLA have created a world map of ancient DNA to show us where in the world the genes of ancient hominids Neanderthals and Denisovans are still prevalent, Fox News reported.
The study also illuminated the benefits and drawbacks of having ancient DNA and what this latest discovery tells us about how and when our human ancestors interbred with each other.
Neanderthals lived 40,000 years ago in Europe during the Stone Age, and in 2010, evidence was revealed that suggested humans had sex with them and reproduced, CNN added. The Denisovans are far more mysterious, and scientists believe they share origins with Neanderthals.
Data on the prevalence of these hominids’ genes in present populations was uncovered by looking at 250 genomes from 120 non-African populations; this data was derived from the publicly available Simons Genome Diversity Project. The modern data was compared to known Neanderthal and Denisovan gene sequences.
With the exception of African people, our modern genome is 2 percent Neanderthal (we starting getting amorous with the ancient people after we left Africa). Denisovan DNA is much higher in some populations at 5 percent, an amount and prevalence that surprised researchers.
More specifically, people in Oceania have the highest percentage of genes from both. People from Papua New Guinea and Australians have the most Denisovan DNA, followed by South Asians, then East Asians and Native Americans. Western Europeans have none.
This data shows that our ancestors had sex with Neanderthals and Denisovans more than once, and all over the world. Scientists had previously assumed that we only shared a bed with Denisovans one time in our shared history, when the populations met and mixed and their offspring moved to East Asia and the Pacific Islands. Now they think Homo sapiens bred with Denisovans in three different spots.
“It is happening repeatedly, wherever modern humans are coming into contact with these archaic people,” said anthropologist John Hawks.
As for how this ancient bed-hopping effects modern people, the Neanderthals gave us thicker hair and tougher skin, while Denisovans helped us live at high altitudes and gave us a good sense of smell. Earlier research found the latter boosted our immunity and helped us survive.
“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 Harvard geneticist David Reich.
But certain traits also died out. For example, both Neanderthals and Denisovans had less-impressive language skills than ours, and the gene associated with that ability wasn’t passed on — our superior one prevailed.
But the most interesting consequence of our interbreeding involved reproduction. Scientists found that the offspring of Neanderthal/human and Denisovan/human mating weren’t very fertile and had a harder time passing on their mixed genes. This is often the case when animals of different species reproduce.
This ancient hanky-panky can tell scientists a lot, except how these populations migrated or how Neanderthals and Denisovans looked, what they ate, or how they got sick. At the very least, the study is “very cool,” according to the man who first suggested that humans mated with Neanderthals 50,000 years ago, evolutionary geneticist Svante Pääbo.
“It is especially interesting that just as the genetic interactions with Neanderthals in Europe and western Asia seem to have been numerous and contributed some important gene variants to present-day people, in eastern and southern Asia similar things seem to have gone with the Denisovans. It is cool that Neanderthals and Denisovans are not totally extinct. Parts of them live on in people today.”
The oldest Neanderthal DNA was recently found, the Inquisitr previously reported.
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