The researchers also found skeleton genes changed more than expected within the Neanderthal lineage.
"For example, genes that affect the curvature of the spine have changed in Neanderthals," Pääbo said. "This fits with how their skeletons have changed quite drastically during their evolution."
On the other hand, genes involved with pigmentation and behavior changed more in the modern human lineage.
"We do not yet know if and how these very mutations affect behavior," Pääbo said. "Clearly, it will be interesting to study more Neanderthals so that one can begin to reconstruct their history in more detail."
The scientists detailed their findings online today (April 21) in the journal Proceedings of the National Academy of Sciences.
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