Neandertals aren't the only hominin line that branched off from humans a long time ago and later bred with humans. Ancient hominins named Denisovans (after a Siberian cave where their remains were found) bred with humans as shown by DNA sequence comparison. Recently scientists in Svante Pääbo's lab did a full DNA sequence of a Denisovan girl who died tens of thousands of years ago in Siberia.
In a stunning technical feat, an international team of scientists has sequenced the genome of an archaic Siberian girl 31 times over, using a new method that amplifies single strands of DNA. The sequencing is so complete that researchers have as sharp a picture of this ancient genome as they would of a living person’s, revealing, for example that the girl had brown eyes, hair, and skin. “No one thought we would have an archaic human genome of such quality,” says Matthias Meyer, a postdoc at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. “Everyone was shocked by the counts. That includes me.”
The Denisovan girl might have died 80,000 years ago. See the Scientific American coverage by Katherine Harmon for implications this discovery has for migrations of early humans.
The analysis suggests that the modern human line diverged from what would become the Denisovan line as long as 700,000 years ago—but possibly as recently as 170,000 years ago.
Bringing Denisovans back to life would let us better study the effects of their genetic variants. Suppose it is found that the Denisovans have some genetic variants that would be useful in humans. Should it be legal to add these genetic variants into human offspring?
I expect scientists who work with cell cultures will do something less radical first: integrate sections of Denisovan DNA into human cells in culture. Then watch how their genes get expressed in different conditions in cell culture. If scientists integrate some of that DNA into lab mice then Denisovan DNA expression could be studied even more realistically.
|Share |||Randall Parker, 2012 September 02 02:23 PM Evolution Primates|