DNA scan sheds new light on mankind's mysterious cousins (Update)

Aug 30, 2012
Denisova molar, distal. Image courtesy of Max Planck Institute for Evolutionary Anthropology

Max Planck researchers describe Denisovan genome, illuminating the relationships between Denisovans and present-day humans.

The analyses of an international team of researchers led by Svante Pääbo of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, show that the genetic variation of Denisovans was extremely low, suggesting that although they were present in large parts of Asia, their population was never large for long periods of time. In addition, a comprehensive list documents the genetic changes that set apart modern humans from their archaic relatives. Some of these changes concern genes that are associated with brain function or nervous system development.

In 2010 Svante Pääbo and his colleagues sequenced DNA that they isolated from a finger bone fragment discovered in the Denisova Cave in southern Siberia. They found that it belonged to a young girl of a previously unknown group of archaic humans that they called "Denisovans". Thanks to a novel technique which splits the DNA double helix so that each of its two strands can be used for sequencing, the team was able to sequence every position in the Denisovan genome about 30 times over. The thus generated genome sequence shows a quality similar to genomes that have been determined from present-day humans.

Matthias Meyer at work in the clean lab. Credit: MPI for Evolutionary Anthropology

In a new study, which is published in this week's issue of the journal Science, Svante Pääbo and his colleagues compare the Denisovan genome with those of the Neandertals and eleven modern humans from around the world. Their findings confirm a previous study according to which modern populations from the islands of southeastern Asia share genes with the Denisovans. In addition, the genomes of people from East Asia, and South America include slightly more genes from Neandertals than those of people in Europe: "The excess archaic material in East Asia is more closely related to Neandertals than to Denisovans, so we estimate that the proportion of Neandertal ancestry in Europe is lower than in eastern Asia", the Leipzig researchers report.

This is a replica of the finger bone fragment of a Denisovan hominin on a human hand. Credit: MPI for Evolutionary Anthropology

"This is an extinct genome sequence of unprecedented accuracy", says Matthias Meyer, the lead author of the study. "For most of the genome we can even determine the differences between the two sets of chromosomes that the Denisovan girl inherited from her mother and father". From this the researchers can tell that genetic variation of the Denisovans was lower than in present-day humans. This is likely due to that an initially small Denisovan population that grew quickly while spreading over a wide geographic range. "If future research of the Neandertal genome shows that their population size changed over time in similar ways, it may well be that a single population expanding out of Africa gave rise to both the Denisovans and the Neandertals", says Svante Pääbo, who led the study.

The researchers furthermore generated a list of about 100,000 recent changes in the human genome that occurred after the split from the Denisovans. Some of these changes affect genes that are associated with brain function and nervous system development. Others possibly affect the skin, the eye and dental morphology. "This research will help determining how it was that modern human populations came to expand dramatically in size as well as cultural complexity while archaic humans eventually dwindled in numbers and became physically extinct", says Svante Pääbo.

Earlier this year, the Leipzig researchers had already made the entire Denisovan genome sequence available to the broader public by publishing it online.

Explore further: Archaeologists, tribe clash over Native remains

More information: Matthias Meyer, Martin Kircher, Marie-Theres Gansauge, Heng Li, Fernando Racimo, Swapan Mallick, Joshua G. Schraiber, Flora Jay, Kay Prüfer, Cesare de Filippo, Peter H. Sudmant, Can Alkan, Qiaomei Fu, Ron Do, Nadin Rohland, Arti Tandon, Michael Siebauer, Richard E. Green, Katarzyna Bryc, Adrian W. Briggs, Udo Stenzel, JesseDabney, Jay Shendure, Jacob Kitzman, Michael F. Hammer, Michael V. Shunkov, Anatoli P. Derevianko, Nick Patterson, Aida M. Andrés, Evan E. Eichler, Montgomery Slatkin, David Reich, Janet Kelso, Svante Pääbo A high coverage genome sequence from an archaic Denisovan individual Science, August 30, 2012

Related Stories

Entire genome of extinct human decoded from fossil

Feb 07, 2012

(PhysOrg.com) -- In 2010, Svante Pääbo and his colleagues presented a draft version of the genome from a small fragment of a human finger bone discovered in Denisova Cave in southern Siberia. The ...

New ancestor? Scientists ponder DNA from Siberia

Mar 24, 2010

(PhysOrg.com) -- An international team of scientists from the Max Planck Institute for Evolutionary Anthropology in Leipzig has sequenced ancient mitochondrial DNA from a finger bone found in southern Siberia. ...

Shared genes with Neanderthal relatives not unusual

Oct 31, 2011

During human evolution our ancestors mated with Neanderthals, but also with other related hominids. In this week's online edition of PNAS (Proceedings of the National Academy of Sciences), researchers from Uppsala Univer ...

Recommended for you

Archaeologists, tribe clash over Native remains

16 hours ago

Archaeologists and Native Americans are clashing over Indian remains and artifacts that were excavated during a construction project in the San Francisco Bay Area, but then reburied at an undisclosed location.

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

yonko
3 / 5 (2) Sep 02, 2012
awesome detective work, scientists!!!

More news stories

Male-biased tweeting

Today women take an active part in public life. Without a doubt, they also converse with other women. In fact, they even talk to each other about other things besides men. As banal as it sounds, this is far ...

Not just the poor live hand-to-mouth

When the economy hits the skids, government stimulus checks to the poor sometimes follow. Stimulus programs—such as those in 2001, 2008 and 2009—are designed to boost the economy quickly by getting cash ...

Archaeologists, tribe clash over Native remains

Archaeologists and Native Americans are clashing over Indian remains and artifacts that were excavated during a construction project in the San Francisco Bay Area, but then reburied at an undisclosed location.

When things get glassy, molecules go fractal

Colorful church windows, beads on a necklace and many of our favorite plastics share something in common—they all belong to a state of matter known as glasses. School children learn the difference between ...

FCC to propose pay-for-priority Internet standards

The Federal Communications Commission is set to propose new open Internet rules that would allow content companies to pay for faster delivery over the so-called "last mile" connection to people's homes.