. Earth Science News .
ABOUT US
The fate of Neanderthal genes
by Staff Writers
Davis CA (SPX) Nov 09, 2016


So what happened to the Neanderthal DNA? Today, Neanderthal genes are a few percent of the genome of people of European ancestry, a little more common in people of East Asian descent, and almost absent in people of African ancestry.

The Neanderthals disappeared about 30,000 years ago, but little pieces of them live on in the form of DNA sequences scattered through the modern human genome. A new study by geneticists at the University of California, Davis, shows why these traces of our closest relatives are slowly being removed by natural selection.

"On average, there has been weak but widespread selection against Neanderthal genes," said Graham Coop, professor in the UC Davis Department of Evolution and Ecology and Center for Population Biology, and senior author on a paper describing the work published Nov. 8 in the journal PLOS Genetics. That selection seems to be a consequence of a small population of Neanderthals mixing with a much larger population of modern humans.

Neanderthals split from our African ancestors over half a million years ago, and lived in Europe and Central Asia until a few tens of thousands of years ago. Archaeological discoveries have shown that they had quite a sophisticated culture, Coop said. Thanks to DNA samples retrieved from a number of fossils, we have enough data on the Neanderthal genome to identify their genes among ours.

When modern humans left Africa about 50,000 to 80,000 years ago and spread through Europe and Asia, they interbred with Neanderthals. The first hybrid offspring would have been, on average, a 50-50 mix of modern human and Neanderthal genes, and could then have themselves bred with modern humans, Neanderthals or other hybrids.

So what happened to the Neanderthal DNA? Today, Neanderthal genes are a few percent of the genome of people of European ancestry, a little more common in people of East Asian descent, and almost absent in people of African ancestry.

Coop and postdoctoral researchers Ivan Juric and Simon Aeschbacher devised methods to measure the degree of natural selection acting on Neanderthal DNA in the human genome.

One hypothesis has been that Neanderthals quickly became genetically incompatible with modern humans, so their hybrid offspring were not "fit" in evolutionary terms - they either failed to thrive or were not fertile.

Weak but Widespread Selection Against Neanderthal Genes
The researchers found something different. Rather than showing strong selection against a few Neanderthal genes, they found weak, but widespread selection against many Neanderthal DNA sequences that is slowly removing it from our genome.

Coop said that's consistent with a small, isolated population of Neanderthals mixing with a much larger population of modern humans. Inbreeding in small populations means that genetic variants can remain common even if they're harmful to some degree. But when they mix into a larger population, natural selection starts to act against those variants and weed them out.

"The human population size has historically been much larger, and this is important since selection is more efficient at removing deleterious variants in large populations," Juric said. "Weakly deleterious variants that could persist in Neanderthals could not persist in humans. We think that this simple explanation can account for the pattern of Neanderthal ancestry that we see today along the genome of modern humans."

The findings are consistent with other recently published work. If Neanderthals had been more numerous when modern humans encountered them, we might have a different mix of Neanderthal and human genes, Juric said.

Research paper


Comment on this article using your Disqus, Facebook, Google or Twitter login.


Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.
SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only


.


Related Links
University of California - Davis
All About Human Beings and How We Got To Be Here






Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

Previous Report
ABOUT US
Resilient 'risky-and-reliable' plant use strategy may have driven Neolithization in Jordan
Washington DC (SPX) Oct 24, 2016
A resilient dietary strategy balancing reliable wetland plants and "riskier" seasonal grasses may have driven adoption of the sedentary lifestyle which later became typical of Neolithic humans, according to a study published October 19, 2016 in the open-access journal PLOS ONE by Monica Ramsey from the University of Toronto, Canada, and colleagues. Neolithization - the development of human ... read more


ABOUT US
Haiti aid hard to come by one month after hurricane

Brazil mine gets safety gear -- too late

Italy quake zones fear tourism collapse as displaced total rises

Colombian president 'inspired' by N. Irish peace process

ABOUT US
Trace metal recombination centers kill LED efficiency

Controlling the properties of matter in two-dimensional crystals

Lehigh scientists fabricate a new class of crystalline solid

Establishing an advanced bonding technique for tungsten and copper alloys

ABOUT US
Nightlights under the sea

Ocean glider sets sail on longest journey of its kind

Economic impact of inland waterway disruptions: Potentially billions

Brazil dam burst like 'end of the world'

ABOUT US
Kerry to be first US top diplomat to visit Antarctica

How much Arctic sea ice are you melting? Scientists have the answer

Why does our planet experience an ice age every 100,000 years?

Factors promoting growth of cryoconite granule formation and glacial-ice sheet melting

ABOUT US
How the chicken crossed the Red Sea

Rain, hail and drought: organic French winemakers feel the pinch

Forests, locals harmed in Mexico's avocado boom

Controlling plant regeneration systems may drive the future of agriculture

ABOUT US
Sentinel satellites reveal east-west shift in Italian quake

Popcorn-rocks solve the mystery of the magma chambers

CYGNSS Satellite Mission Aims to Improve Hurricane Forecasting

50 years on, Florence recalls its 'Angels of the Mud'

ABOUT US
President says UN 'scapegoating' Kenyan soldiers in S.Sudan

Deadly clashes in CAR as France ends military mission

Elephant poaching costs Africa tourism $25mn: study

Niger arrests 38 after deadly herder clashes

ABOUT US
Ancient human history more complex than previously thought

Europeans and Africans have different immune systems, and neanderthals are partly to thank

Study finds earliest evidence in fossil record for right-handedness

Extensive heat treatment in Middle Stone Age silcrete tool production in South Africa









The content herein, unless otherwise known to be public domain, are Copyright 1995-2024 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. General Data Protection Regulation (GDPR) Statement Our advertisers use various cookies and the like to deliver the best ad banner available at one time. All network advertising suppliers have GDPR policies (Legitimate Interest) that conform with EU regulations for data collection. By using our websites you consent to cookie based advertising. If you do not agree with this then you must stop using the websites from May 25, 2018. Privacy Statement. Additional information can be found here at About Us.