Paraphyletic - Tumblr Posts

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A letter from a female to a male upon realizing they were left behind when their clan migrated (a poem I wrote earlier, but I thought would be funny in this context)

Neanderthals are dead.

Denisovans are too.

You're the only one left,

So I guess you'll do.

Sure, she’s a little weird looking. But after a few dozen fermented berries, you won’t care (Neanderthal woman reconstruction and photo by University of Zurich).

A paper published in Cell this week describes the results of whole-genome sequencing for five Africans from three hunter/gatherer tribes. The paper reports the discovery of “ancient DNA” sequences in all five Africans. The sequences are previously unknown in modern humans, including other modern Africans, and although the sequences are similar neither to modern humans nor to other human populations — such as Neanderthals — the paper’s authors say the DNA sequences most closely resemble Neanderthals.

One of the paper coauthors, U-Dub genomicist Joshua Akey, told the Washington Post that this was evidence a “sister species” of Neanderthals once roamed Africa (weird because Neanderthals are believed to have originated in Europe and their bones have never been found anywhere in Africa, and Neanderthals were not a species).

It’s not impossible that the gist of what Akey is saying is true — that some population of ancient Europeans went south into Africa and bred with local populations — but the evidence he and his colleagues present is not strong enough to support that claim.

I also disagree with the scientists calling the human source of these ancient DNA sequences a “sister species” of Neanderthals. That suggests the population from which these sequences came were European in origin. We don’t know that.

The New York Times article about the Cell paper is better.

At stake here is how modern humans came into being.

The old idea is that our ancestors originated in Africa, then migrated and replaced populations of human-like (but nonhuman) species wherever they ended up.

The newer, more accepted idea is that new humans (who originated in Africa) actually interbred with older humans wherever they went, and this melding of genes helped produce the world’s many unique groups of modern humans.

Despite what the Post and Times articles suggest, Neanderthals were not a separate species — they were human. And so too could the genetic sequences found in these Africans have come from another group of early humans, perhaps endemic to Africa, as yet unnamed, and roaming through and amidst populations of more modern humans, occasionally interbreeding and mixing new genes with old, old genes with new. Gene flow works both ways, after all.