by Brian Thomas, M.S.

Widespread news reported that scientists sequenced ancient DNA from an extinct human variety that they called a Denisovan in unprecedented detail for ancient DNA. In 2011, researchers reported DNA sequence from the tiny finger bone that had been lying in Siberia’s Denisova Cave, but the sequence was not of high enough quality to compare base-for base to the modern human genome.1 Now it is.

Researcher Matthias Meyer pioneered a technique that sequences ancient and, therefore, fragmented single strands of DNA. Older methods could only sequence larger, double-stranded DNAs.

Meyer was lead author of a paper published in Science,2 successful in “producing a ‘near-complete’ catalog of the small number of genetic changes that make us different from the Denisovans, who were close relatives of Neandertals,” according to Science writer Ann Gibbons.3 So, what kind of creature do the Denisovans represent, and what role might they have played in human history?

First, Neandertals were fully human and interbred with modern man.4 Second, this Denisovan DNA only differed from Neandertal by a “small number of genetic changes,” indicating a close relation.

The Denisovan finger bone fragment was initially identified as modern human. And the same cave held fully human tools and bones. Harvard Medical School population geneticist David Reich coauthored the online Science report.2 NPR host Ira Flatow interviewed him:

FLATOW: Do you think that humans might have mated with Denisovans, as they did with Neanderthals?…

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