Subscribe free to our newsletters via your
. Earth Science News .


Subscribe free to our newsletters via your




















ABOUT US
Researchers find ancient DNA preserved in modern-day humans
by Staff Writers
Binghamton NY (SPX) Mar 22, 2016


This is D. Andrew Merriwether, Binghamton University. Image courtesy Binghamton University. For a larger version of this image please go here.

Residents of the remote equatorial islands of Melanesia share fragments of genetic code with two extinct human species. That's the key finding of a new study published in the journal Science. An international team contributed to the research, which compared the DNA sequences of 35 modern people living on islands off the coast of New Guinea with DNA drawn from two early human species: Denisovans, whose remains were found in Siberia, and Neandertals, first discovered in Germany.

"Substantial amounts of Neandertal and Denisovan DNA can now be robustly identified in the genomes of present-day Melanesians, allowing new insights into human evolutionary history," they wrote. "As genome-scale data from worldwide populations continues to accumulate, a nearly complete catalog of surviving archaic lineages may soon be within reach."

D. Andrew Merriwether, a molecular anthropologist at Binghamton University, collected the modern-day blood samples used in the study about 15 years ago in Melanesia. This is the first time full genomes from those samples have been sequenced.

"I'm surprised that these Neandertal and Denisovan genomes made it out to this remote place," he said. "We know people have been there for at least 48,000 years because we find human remains that go back that far, but no one has ever been able to connect them to any other place. When you compare most of their genome sequences, they don't cluster with any other group. They've been there and been isolated for a very, very long time."

Earlier studies have revealed some genetic overlap (about 2 percent) between Neandertals and non-African populations, and little or no Neandertal and Denisovan ancestry among Africans. This new research suggests Neandertals and modern human ancestors intersected at least three times. It also found an overlap of between 1.9 and 3.4 percent in the genetic codes of Denisovans and modern-day Melanesians.

Skepticism about the new findings is entirely appropriate, said Merriwether, who specializes in reconstructing the past using samples from contemporary populations and ancient DNA from the archaeological record.

"Ancient DNA is always damaged and broken into small pieces," he explained. "You only need one molecule of modern DNA to outperform all the ancient DNA."

An independent laboratory did the sequencing of Merriwether's samples. That, combined with a powerful new statistical technique that was used in the analysis, finally convinced him that the genetic similarities were real.

The cost and time involved in sequencing a full human genome has dropped dramatically. The first, completed in 2003, took 13 years and cost about $2.7 million. Today, it's possible to sequence a sample in days for thousands of dollars. Still, this type of research still poses significant challenges.

The human genome contains about 3 billion "letters," and ancient samples are difficult to work with. When people die, their DNA starts breaking down immediately, Merriwether noted, and it isn't repaired anymore. Normally, a person's DNA is fixed thousands of times a minute. Bacteria and fungi contaminate most DNA samples taken from human remains, he said, making up as much as 97 percent of the DNA that's recovered.

Even collecting the modern samples wasn't a simple task.

Merriwether and longtime collaborator Jonathan Friedlaender of Temple University obtained blood samples throughout the Bismarck Archipelago in the late 1990s and early 2000s. They traveled with George Koki of the Institute for Medical Research in Papua New Guinea and Heather Norton, then a student at Penn State and now a faculty member at the University of Cincinnati.

"It's challenging to reach these places," Merriwether said. "They're volcanic islands with mountains. It's also the most linguistically diverse place on Earth."

How diverse? People in this region speak some 800 languages. A common trading language (Tok Pisin) that's a mix of Polynesian and English helped make it possible for the anthropologists to communicate with residents.

Because malaria is so prevalent in the region, there are many clinics set up to test and treat people. That also meant Merriwether and his colleagues usually weren't the first people asking residents of these islands for blood samples.

Studies like this one may enable scientists to answer big questions about human migrations and evolution thousands of years ago.

Merriwether is particularly fascinated by the Denisovan DNA fragments found in the Melanesian genomes. How did ancient humans travel - and cross the ocean - to get to Melanesia, and when and where did the Denisovan DNA enter our gene pool? Sequencing of additional DNA samples found in Asia may one day help to answer those questions.

"Most people know back a few generations, maybe five generations," Merriwether said, "but where did we come from before that? That's what we want to find out."

Research paper: Excavating Neandertal and Denisovan DNA from the genomes of Melanesian individuals

.


Related Links
Binghamton University
All About Human Beings and How We Got To Be Here






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

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

Previous Report
ABOUT US
How the brain detects short sounds
Salt Lake City UT (SPX) Mar 17, 2016
For humans to understand speech and for other animals to know each other's calls, the brain must distinguish short sounds from longer sounds. By studying frogs, University of Utah researchers figured out how certain brain cells compute the length of sounds and detect short ones. In addition to pitch and loudness, "sound duration is of universal importance," says biology professor Gary Rose ... read more


ABOUT US
Two schoolchildren killed, nine missing in Pakistan avalanche

Hope fades to fear for Chinese refugees in junta-run Thailand

Maths could help search and rescue ships sail more safely in heavy seas

Prince Harry hopes to draw focus to quake-hit Nepal with visit

ABOUT US
A foldable material that can change size, volume and shape

The world's blackest material is now in spray form

New insights into atomic disordering of complex metal oxides

How to make porous materials dry faster

ABOUT US
Ocean acidification along California coast most damaging at night

Ocean acidification takes a toll on California's coastline at nighttime

Coral bleaching at Barrier Reef 'severe': Australia

Calfornia reservoirs get respite but drought still on

ABOUT US
Digging deeper: Study improves permafrost models, reduces uncertainties

Climate warming accelerating carbon loss from thawing Arctic soils

Nature study reveals rapid ice-wedge loss across Arctic

Early Earth was colder than previously thought

ABOUT US
French MPs slash 'Nutella tax' after Indonesia, Malaysia protest

Hindu cow activists drink pesticide in India, one dies

Mongolia herders face disaster: Red Cross

Sorghum: Not so ho-hum

ABOUT US
Wetland enhancement in Midwest could help reduce catastrophic floods of the future

Pakistan rains leave 42 dead: officials

Japan's tsunami: Five things after five years

Pakistan rains leave 28 dead: officials

ABOUT US
Kenya army says killed 34 Shebab in Somalia firefights

Nigeria's ex-defence chief raided staff salary funds to buy property, court told

China and Gambia resume diplomatic ties: ministry

Bank of China gains foothold in Morocco

ABOUT US
400,000-year-old fossils from Spain provide earliest genetic evidence of Neandertals

How the brain detects short sounds

Neanderthal diet: Only 20 percent vegetarian

Early human habitat, recreated for first time, shows life was no picnic




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - 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. 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. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.