The Union Recorder

Homepage

January 30, 2014

Studies find Neanderthal genes in modern humans

WASHINGTON — Neanderthal genes lurk among us. Small traces of Neanderthal DNA have been confirmed in the areas of the genome that affect skin and hair of modern humans, according to two new studies that also give clues as to which Neanderthal traits may have been helpful - or harmful - to the survival of our species.

The studies, published online Wednesday in the journals Nature and Science, came to similar conclusions despite using vastly different methods of genomic analysis.

For East Asian and European populations, genes that provide the physical characteristics of skin and hair have a high incidence of Neanderthal DNA - possibly lending toughness and insulation to weather the cold as early man emerged from Africa, the studies conclude. Neanderthals were thought to have already been adapted to a chillier, more northern environment.

Perhaps most notably, Neanderthal DNA was not found in genes that influence testicles, according to the Nature study, hinting that when the Neanderthal ventured outside his own species for sex, the introduction of his DNA may have reduced male fertility in early humans.

"There's strong evidence that when the two met and mixed, they were at the edge of biological compatibility," said Nature study author and Harvard University geneticist David Reich. "The people who eventually survived and thrived had quite a bit of hurdles to overcome."

This is consistent with what is seen in nature: When two species mate that are sufficiently far away biologically, the resulting hybrids tend to have lowered fertility. Early humans and Neanderthals interbred about 40,000 to 80,000 years ago around the Middle East, during man's migration out of Africa.

And the last Neanderthals died off some 30,000 years ago.

Reich's team used an ancient genome his lab had sequenced last year - as high-quality as any modern DNA data set - from a 130,000-year-old female Neanderthal's toe bone found in a Siberian cave. They compared her data with 1,004 genomes of present-day humans, including those of sub-Saharan Africans. The Science study, led by University of Washington geneticist Joshua Akey, only used East Asian and European sequences, because indigenous Africans possess little or no traces of Neanderthal.

Because Neanderthals occupied Europe and Asia, African ancestors did not have the opportunity to interbreed with them. Reich and his colleagues used the African sequences as a sort of negative control; if parts of the ancient genome were found in East Asians and Europeans, but not in Africans, then those parts may have carried over from Neanderthals.

"Although it's true that each individual has only a small percentage of Neanderthal DNA, the small sequence that I carry might be different than the amount that you carry," Akey said. Non-African humans inherit about 1 to 3 percent of their genomes from Neanderthal ancestors, with East Asians tending to have a slightly larger proportion than Europeans.

In total, he found that all the sequence bits among his analysis population of 379 European and 286 East Asian subjects, in total, spanned about 20 percent of the Neanderthal genome. As opposed to Reich, Akey scanned the modern genomes without comparing against the ancient DNA, finding regions that were likely to be contributed by a certain era's ancestors. Only later did he compare those parts with the Neanderthal reference genome.

Geneticist Edward Rubin of the Lawrence Berkeley National Laboratory, who was not involved in the studies but has sequenced sections of the Neanderthal genome, found the results plausible and interesting.

 "I was stunned by the public interest in Neanderthals," he said. "Everybody wanted to know two things: whether we had sex with them, and we did, and what happened to them."

 Their DNA has confirmed interbreeding, but scientists don't know why these hominids failed to survive. Theories abound; some suggest a violent genocide at the hands of Homo sapiens, others say they fell short and died off.

 "They kind of disappear from the archeological record, and it's tempting to think that they were out-competed for resources," Reich said. "But we know they got incorporated into modern humans, and they live on in us today."

 

1
Text Only
Local News
web break-1.jpg

Features
SRC 5.jpg

The Teen Club, as part of the Twin Lakes Library System's Summer Reading Club, and Reference Supervisor Dabney Kinser do candy science experiments to finish up the science themed reading club experience.

Business
07-25 Chatter.JPG

Chatter Boutique owner Amber Patitucci shows off a new shipment of jewelry. The former educator turned businesswoman is celebrating one year of business. To commemorate the event, the store is featuring a birthday bash sale with items at half price.

Local Sports
Editorials
Columns
Letters
Local Weather Radar
Poll
AP Video
Raw: Air Algerie Flight 5017 Wreckage Virginia Governor Tours Tornado Aftermath Judge Faces Heat Over Offer to Help Migrant Kids Kerry: No Deal Yet on 7-Day Gaza Truce Kangaroo Goes Missing in Oklahoma More M17 Bodies Return, Sanctions on Russia Grow Gaza Residents Mourn Dead Amid Airstrikes Raw: Deadly Tornado Hits Virginia Campground Ohio State Marching Band Chief Fired After Probe Raw: Big Rig Stuck in Illinois Swamp Cumberbatch Brings 'Penguins' to Comic-Con Raw: Air Algerie Crash Site in Mali Power to Be Restored After Wash. Wildfire Crashed Air Algerie Plane Found in Mali Israel Mulls Ceasefire Amid Gaza Offensive In Case of Fire, Oxygen Masks for Pets Mobile App Gives Tour of Battle of Atlanta Sites
Facebook
Twitter Updates
Follow us on twitter
Parade
Magazine

Click HERE to read all your Parade favorites including Hollywood Wire, Celebrity interviews and photo galleries, Food recipes and cooking tips, Games and lots more.
Stocks
NDN Video
What's Got Jack Black Freaking Out at Comic-Con? Doctors Remove 232 Teeth From Teen's Mouth Bradley Cooper Explains His Voice in 'Guardians of the Galaxy' Deja vu: Another NYPD officer choke-holding a suspect Chapter Two: Becoming a first-time director 'Fifty Shades of Grey': Watch the Super Sexy First Trailer Now! Reports: Ravens RB Ray Rice Suspended For 1st 2 Games Of The Season Air Algerie plane with 119 on board missing over Mali Diamond Stone, Malik Newman, Josh Jackson and others showcase talent Free Arturo - The World's Saddest Polar Bear A Look Back at Batman On Film Through The Years LeBron James -- Dropped $2k On Cupcake Apology ... Proceeds To Benefit Charity Snoop Dogg Says He Smoked Weed at the White House Raw: Fight Breaks Out in Ukraine Parliament Chris Pratt Interrupts Interview To French Braid Intern's Hair Shirtless Super Mario Balotelli Dances While Ironing - @TheBuzzeronFOX Whoa! Watch "Housewives" Star Do the Unthinkable LeBron apologizes to neighbors with cupcakes Justin Bieber In Calvin Klein Underwear Shoot Samsung Pre-Trolls The IPhone 6 With New Ad