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Neanderthal DNA may account for nicotine addiction and depression





Matching modern genetic profiles against genes known to have been
inherited from Neanderthals has shown links to a wide range of current disorders






The study discovered associations between Neanderthal DNA and a
wide range of modern traits, including immunological, dermatological, neurological, psychiatric and reproductive diseases.
The study discovered associations between Neanderthal DNA and a wide
range of modern traits, including immunological, dermatological,
neurological, psychiatric and reproductive diseases. Photograph:
Michael Smeltzer/Vanderbilt Univ/PA


Tim Radford

Thursday 11 February 2016 15.00 EST Last modified on Thursday 11
February 2016 15.03 EST

Modern European and Asian people may owe more than skin or hair colour
to Neanderthal ancestry. Interbreeding 50,000 years ago between two
species of human may also have bequeathed a sunburn hazard called
keratosis, addiction to nicotine, and a greater risk of depression.

That the forebears of modern Homo sapiens and the long-extinct
Neanderthals lived side by side is well known: that they interbred,
and that up to 4% of modern human DNA is inherited from the first
Europeans, was confirmed only in 2010.







Human-Neanderthal relationships may be at root of modern allergies








US researchers examined a database of 28,000 patients whose biological
samples had been linked to versions of their medical records.
Identities remained anonymous but the researchers could see how
inheritance linked to medical history.

Then, they report in the journal Science, they matched the modern
human database against a map of those groups of genes known to have
been inherited from the big-boned, heavy-browed, red-haired humans
whose ancestors had moved out of Africa long before Homo sapiens, and
colonised Ice Age Europe.

“Our main finding is that Neanderthal DNA does influence clinical
traits in modern humans,” said John Capra, an evolutionary geneticist
at Vanderbilt University in Nashville, Tennessee. “We discovered
associations between Neanderthal DNA and a wide range of traits,
including immunological, dermatological, neurological, psychiatric and reproductive diseases.”

Sub-Saharan African peoples do not inherit Neanderthal DNA. The
assumption is that the Neanderthals left Africa first, had time to
adapt to a colder, darker and more difficult world, evolved paler skin
colour to take advantage of less certain sunlight, and developed other
traits that might have helped them survive changing conditions.

Early modern humans – more gracile, and perhaps quicker to adapt and
take advantage of their environment – then migrated north from Africa
to outpace and outlive the first Europeans. But, during the thousands
of years the two species coexisted, they also interbred.







My Neanderthal sex secret: modern European's great-great grandparent
link







Read more

And these encounters passed on traits that might have been of some
evolutionary advantage in an Ice Age world. But in changing
conditions, the same lengths of inherited DNA contained greater health liabilities as well.




One of these, the researchers think, was a Neanderthal gene variant
that increases blood-clotting. This would have sealed wounds more
quickly, and prevented infection more easily. But in a modern western
society, hyper-coagulation brings other problems, including greater
risk for stroke, pulmonary embolism and pregnancy complications.

One length of Neanderthal DNA is now linked to increased risk of
nicotine addiction, and several variants influence the risk of mood
disorders, including depression. As tobacco was introduced into
widespread use in Europe only 400 years ago, the researchers were
surprised at the number of Neanderthal genetic variants now associated
with modern psychiatric and neurological disorders.

“The brain is incredibly complex, so it is reasonable to expect that introducing changes from a different evolutionary path might have
negative consequences,” said Corinne Simonti, a Vanderbilt doctoral
student .

https://www.theguardian.com/science/2016/feb/11/neanderthal-dna-may-account-for-nicotine-addiction-and-depression

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Research showing that our species interbred with Neanderthals some 100,000 years ago is providing intriguing evidence that Homo sapiens ventured out
of Africa much earlier than previously thought, although the foray appears
to have fizzled.

Scientists said on Wednesday an analysis of the genome of a Neanderthal
woman whose remains were found in a cave in the Altai Mountains in
southern
Siberia near the Russia-Mongolia border detected residual DNA from Homo sapiens, a sign of inter-species mating.

Previous research had established that Homo sapiens and our close cousins
the Neanderthals interbred around 50,000 to 60,000 years ago, said
geneticist Sergi Castellano of the Max Planck Institute for Evolutionary Anthropology in Germany.

The new study, published in the journal Nature, indicates that additional interbreeding also occurred tens of thousands of years earlier.

Our species arose in Africa roughly 200,000 years ago and later migrated
to
other parts of the world.

Geneticist Martin Kuhlwilm of Spain's Universitat Pompeu Fabra, who worked
on the study at the Max Planck Institute, said a very likely scenario explaining the Homo sapiens DNA in theNeanderthal woman's genome is that a small population of ourspecies trekked out of Africa and encountered Neanderthalsin the Middle East, and interbreeding occurred there.

Their journey appears to have been what researchers called a failed
dispersal from Africa, with no descendants going on to colonize Europe,
Asia and points beyond.

"We don't know what happened to them. It seems likely that this population
went extinct, either by environmental changes or maybe direct competition
with Neanderthals," Kuhlwilm said.

"This seems to have happened during a much earlier migration out of Africa
than previously thought. It implies that modern humans left Africa in
several waves, some of which probably went extinct."

The robust, large-browed Neanderthals prospered across Europe and Asia
from
about 350,000 years ago until shortly after 40,000 years ago, disappearing
in the period after our species established itself in the region.

Despite an outdated reputation as our dimwitted cousins, scientists say Neanderthals were highly intelligent, with complex hunting methods, likely
use of spoken language and symbolic objects, and sophisticated fire usage.

Neanderthal interbreeding with Homo sapiens had a lasting impact on human genetics. A study published last week in the journal Science revealed a
link between residual Neanderthal DNA in the human genome and traits in
people including depression, nicotine addiction, blood-clotting and skin lesions.

(Reporting by Will Dunham; Editing by Frances Kerry)

http://www.reuters.com/article/us-science-neanderthals-idUSKCN0VQ2AD

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Research showing that our species interbred with Neanderthals some
100,000
years ago is providing intriguing evidence that Homo sapiens ventured
out
of Africa much earlier than previously thought, although the foray
appears
to have fizzled.

Scientists said on Wednesday an analysis of the genome of a
Neanderthal
woman whose remains were found in a cave in the Altai Mountains in
southern
Siberia near the Russia-Mongolia border detected residual DNA from
Homo
sapiens, a sign of inter-species mating.

Previous research had established that Homo sapiens and our close
cousins
the Neanderthals interbred around 50,000 to 60,000 years ago, said
geneticist Sergi Castellano of the Max Planck Institute for
Evolutionary
Anthropology in Germany.

The new study, published in the journal Nature, indicates that
additional
interbreeding also occurred tens of thousands of years earlier.

Our species arose in Africa roughly 200,000 years ago and later
migrated to
other parts of the world.

Geneticist Martin Kuhlwilm of Spain's Universitat Pompeu Fabra, who
worked
on the study at the Max Planck Institute, said a very likely scenario explaining the Homo sapiens DNA in theNeanderthal woman's genome is
that a
small population of ourspecies trekked out of Africa and encountered Neanderthalsin the Middle East, and interbreeding occurred there.

Their journey appears to have been what researchers called a failed
dispersal from Africa, with no descendants going on to colonize
Europe,
Asia and points beyond.

"We don't know what happened to them. It seems likely that this
population
went extinct, either by environmental changes or maybe direct
competition
with Neanderthals," Kuhlwilm said.

"This seems to have happened during a much earlier migration out of
Africa
than previously thought. It implies that modern humans left Africa in
several waves, some of which probably went extinct."

The robust, large-browed Neanderthals prospered across Europe and Asia
from
about 350,000 years ago until shortly after 40,000 years ago,
disappearing
in the period after our species established itself in the region.

Despite an outdated reputation as our dimwitted cousins, scientists
say
Neanderthals were highly intelligent, with complex hunting methods,
likely
use of spoken language and symbolic objects, and sophisticated fire
usage.

Neanderthal interbreeding with Homo sapiens had a lasting impact on
human
genetics. A study published last week in the journal Science revealed
a
link between residual Neanderthal DNA in the human genome and traits
in
people including depression, nicotine addiction, blood-clotting and
skin
lesions.

(Reporting by Will Dunham; Editing by Frances Kerry)

http://www.reuters.com/article/us-science-neanderthals-idUSKCN0VQ2AD



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