Thursday, December 5, 2013

Baffling 400,000-Year-Old Clue to Human Origins

Carl Zimmer
New York Times
(Link)

“It’s extremely hard to make sense of,” Dr. Meyer said. “We still are a bit lost here.”

It's worth reading palaeontologist John Hawks' article regarding this announcement:
(Link)

From the article:

"For more than a hundred years, scientists have been drawing straight lines connecting different fossils, to try to understand the human family tree. Those straight lines always diverged over time, leading toward increasing specialization and extinction of fossil groups. And for more than twenty-five years, geneticists have been assuming that the lines connecting the genealogy of mtDNA should be the same as the lines connecting the fossils. When those lines were different, geneticists have been happy to toss the fossils out of the human family tree, content to accept the story that the fossil people had become too specialized, too peripheral to be ancestors of today's people.

"But the last five years have made clear that both groups -- the fossil scientists drawing straight lines of diverging fossil populations, and the geneticists drawing straight lines of diverging -- were wrong."

Reading further:

"Maybe the Denisovans were west Asian Neandertals. It does seem like known genetics of Neandertals may represent something like an earlier iteration of the origin of modern humans -- more African than earlier hominins like the Sima sample, less influenced by Eurasian mixture than the Denisova genome, only a subset of the diversity of surrounding contemporaries. But we have no idea what the Neandertals of the Levant or southwest Asia may have been like genetically -- maybe they were more like Denisovans. This is all basically speculation, which indicates how little we still understand about the dynamics of these populations."

"They were complicated. Their relationships cannot be described by drawing straight lines between fossil samples. There were multiple lines of influence among them, small degrees of mixture and large-scale migrations. Europe was far from a slowly evolving population "accreting" Neandertal features over time. The Neandertals we know did not lumber into their doom; they expanded rapidly, multiple times, from non-European origins. They were as dynamic as the Middle Stone Age Africans who would later mix with them and expand across the world."

Good, John.

Don't forget the butterflies!
(Link)

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