Story highlights
- Analysis of genetic information worldwide found that some people had blends of archaic DNA
- Traces of Neanderthal and Denisovan ancestry was found in some Pacific Islanders
(CNN)Neanderthals may not have been as lucky as our human ancestors in the long run, but that doesn't mean the two subspecies didn't get lucky.
Scientists
have discovered that Homo sapiens -- that's us -- made more babies with
archaic humanlike species than initially thought. That sexual history
has left a mark on the human genome, possibly influencing our immune
systems and metabolism, according to a new study published in the journal of Science.
Scientists
analyzed the genetic information of more than 1,500 people from all
around the world and determined that ancestors of modern humans
interbred with Neanderthals and Denisovans.
They learned that some Asians, Europeans and even the Melanesians of Papua New Guinea had Neanderthal and Denisovan ancestry.
Mystery
surrounds the Denisovans, which were related to Neanderthals but
genetically different, in much the same way Neanderthals were distinct
from modern humans. In 2008, fossil remains of Denisovans were
discovered in a cave in Siberia.
The
discovery of traces of Denisovan DNA in the people of Melanesia is
significant because the Pacific Islanders live thousands of miles away
from the Siberian region that Denisovans are believed to have existed.
"It
is still not exactly clear when and where Melanesian ancestors crossed
paths with Denisovans, but our best guess is somewhere in mainland
Southeast Asia," University of Washington evolutionary geneticist Joshua
Akey, who helped lead the study, told CNN.
This is a likely scenario based on the low levels of Denisovan ancestry found in some South Asian populations.
The
study confirms early theories that our human ancestors interbred with
other hominins after they left Africa more than 50,000 years ago.
"What
was surprising from our study is that it revealed the history of
contact with Neanderthals was more complicated than previously
anticipated," Akey said.
And those
sexual encounters may have played an important role in bestowing humans
with biology that impacts our skin and hair, giving us
infection-fighting advantages. "Many of these genes are involved in
immunity and likely helped our ancestors fight new pathogens that they
were exposed to as they dispersed into new environments," Akey said.
The
research discovered that all non-Africans who were analyzed in the
study had traces of Neanderthal, and different groups from Europe, Asia
and Melanesia had distinctive blends of Neanderthal genes, which likely
means humans repeatedly ran into these hominins, according to Benjamin
Vernot, a postdoctoral student in genomic sciences at the University of
Washington, who led the project.
"Studies like ours help to better understand the sources contributing to patterns of human genomic diversity," Akey said.
This study gives scientists new clues about the archaic DNA that may have influenced traits in modern humans.
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