Razib Khan One-stop-shopping for all of my content

October 18, 2012

The original Africans are Neandertals (in part)

Filed under: Anthroplogy,Neanderthal — Razib Khan @ 1:10 am

In antiquity what we term Tunisia and Tripolitania were part of “African province.” Just as “Asia” originally referred to the margins of what we now term Asia (regions of Anatolia), so “Africa” originally denoted a subset of the northwest fringe of the continent which became Africa. In biogeography this segment of the continent is actually not part of Africa (it is part of the Palearctic ecozone). And yet the vicissitudes of early modern cartography are such that continent had to be bounded by water on as many sides as possible, and today we clumsily make recourse to the term “Sub-Saharan Africa” to distinguish that region from the northern littoral, which is really part of the Mediterranean world.

This context is somewhat relevant when we evaluate a new PLoS ONE paper, North African Populations Carry the Signature of Admixture with Neandertals. This paper makes little sense unless you’ve read an earlier one, Genomic Ancestry of North Africans Supports Back-to-Africa Migrations. In that paper authors make the case that a majority of the ancestry of modern Maghrebis seems to date back to before the Neolithic, from a late ...

July 19, 2011

What did red-haired Neanderthals look like?

So asks a commenter below in relation to the question above. First, why would one even presume that they were red-haired, see my 2007 post, or the paper in Science: A Melanocortin 1 Receptor Allele Suggests Varying Pigmentation Among Neanderthals. In humans loss of pigmentation can usually be thought of as loss of function on genes. That’s probably one reason that there are several different genetic architectures for light skin, but only one for very dark skin. There might be only one way for an engine to operate as designed, but there are many different ways you can tweak a part and render it broken.

The reason that scientists have posited that Neanderthals were red-haired is that they examined the region around a melanocortin receptor gene which serves as something of a master regulator in terms of melanin production. Their sample was of two Neanderthals, one from Italy and one from Spain, and both exhibited signs of loss of function within this region. An N = 2 is small, but one must recall the fact that they are independent draws as they were sampled from different regions. Also, since then from what I ...

May 6, 2010

Breaking: there’s a little bit of Neandertal in all of us

Filed under: Anthroplogy,Evolution,Human Evolution,Neandertal,Neanderthal — Razib Khan @ 10:00 am

We’re all a bit of a Neanderthal:

As a result, between 1pc [percent] and 4pc of the DNA of non-African people alive today is Neanderthal, according to the research. The discovery emerged from the first attempt to map the complete Neanderthal genetic code, or genome. It more or less settles a long-standing academic debate over interbreeding between separate branches of the human family tree. Evidence in the past has pointed both ways, for and against modern humans and Neanderthals mixing their genes.

Prof Svante Paabo, of the Institute for Evolutionary Anthropology in Leipzig, Germany, said: “Those of us who live outside Africa carry a little Neanderthal DNA in us.”

eva-green-picture-1I will have a thorough write-up when I get a hold of the paper, which should be soon. As I said, this is a story of genomics, not just genetics. 1-4% is not trivial. The Daily Telegraph has more:

They were surprised to find that Neanderthals were more closely related to modern humans from outside Africa than to Africans.

Even more mysteriously, the relationship extended to people from eastern Asia and the western Pacific – even though no Neanderthal remains have been found outside Europe and western Asia.

The most likely explanation is that Neanderthals and Homo sapiens interbred before early modern humans struck out east, taking traces of Neanderthal with them in their genes.

Professor Svante Paabo, director of evolutionary genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who led the international project, said: “Since we see this pattern in all people outside Africa, not just the region where Neanderthals existed, we speculate that this happened in some population of modern humans that then became the ancestors of all present-day non-Africans.

“The most plausible region is in the Middle East, where the first modern humans appeared before 100,000 years ago and where there were Neanderthals until at least 60,000 years ago.

“Modern humans that came out of Africa to colonise the rest of the world had to pass through that region.”

Several genes were discovered that differed between Neanderthals and Homo sapiens and may have played important roles in the evolution of modern humans.

They included genes involved in mental functions, metabolism, and development of the skull, collar bone and rib cage.

Image Credit: United Press International

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