Neandertal & H. sapiens sapiens interbreeding

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Modern Humans, Neanderthals May Have Interbred:

“To me, what happened is that the Neanderthals were [genetically] absorbed into and overwhelmed by modern humans coming into Europe from Africa, and they disappeared through this absorption,” Trinkaus said.

Examining the bones, Trinkaus discovered certain features that he believes are Neanderthal elements incorporated into this early Homo sapien.

Features at the back of the woman’s skull and in her lower jaw, especially, “are found in high frequency in Neanderthals” but are absent in bones from older groups of Homo sapiens from Africa, he said.

The paper will be on the PNAS site sometime this week, apparently it is behind an ‘embargo wall’ right now and already in circulation amongst those with special access. This is a morphology story, it seems that individuals with a mosaic of African and Neandertal traits existed in Europe ~30,000 years ago. What does this tell us? If we didn’t have the genetic evidence I think one would have to assume that the highest likelihood is that some interbreeding went on. But didn’t we learn last week that humans and Neandertals were separate and distinct lineages, with the latter contributing nothing to the genome of the former?

1) Not all regions of the genome are created equal when it comes to a particular phenotype (e.g., if you looked at Y lineages Mexican Americans should be Spaniards, if you looked at mtDNA lineages they should be Amerindians, and yet they are a mix of both when it comes to the vast majority of their genome, the Y & mtDNA just happen to be convenient for genetic analysis).

2) Selection can operate on specific regions of a genome independently from others. This is why you see “selective sweeps” across lengths of sequence while neutrality seems to be operative elsewhere.

3) There nature of genomic sequences shaped by neutral evolution vs. those subject to selective forces can differ a great deal because of the alternative dynamics at work as a function of time. The former can be far more informative about ancestry than the latter because in the case of the latter not all ancestors are created equal.

4) There are always papers in the pipeline which can modulate your priors. One should credit Trinkaus et. al. because of other pieces of data which will come to light in the near future.

8 Comments

  1. The piece of (non-genetic) data that always impressed me, and led me toward my previous hypothesis, is that toward the end of their history, Neanderthal cultural evolution started speeding up. To me, this points toward introgression in both directions – i.e. assimilation.

  2. Thank you for all these tips. 
     
    because of other pieces of data which will come to light in the near future.  
     
    Should you ever be involved in some big stock deal, a genetic engineering startup perhaps, please watch out for the SEC. They go after people who know too much. ;-)

  3. The Otomí people? Wrong. I’ll go with David Boxenhorn.  
     
    So, the Lake Superior region is crawling with neandertals… 
     
    http://www.lmic.state.mn.us/datanetweb/maps/ancestry/us/finnish.gif

  4. >>with the latter contributing nothing to the genome of the former? 
     
    Modern Europeans may have no link with the H. sapiens sapiens that first entered Europe.One can see in recent history whole populations can be replaced very quickly eg USA, Australia. 
     
    I have seen no evidence that connects say Basque Y dna with Europeans 30,000 years ago. 
     
    >>..coming into Europe from Africa. 
     
    I thought Europeans are supposed to have arrived from central Asia/Middle East, this seems to confirm my point above. 
     
    Hence if there was mixing 30,000 years ago,then modern Europeans where not present in Europe at that time and their entry in Europe was more recent.

  5. Here’s something else:”The bone is that of a Homo sapiens, or modern man, but the tooth is extremely archaic, similar to that of a Neanderthal. We don’t know yet what it is exactly. Do we have a very old Homo sapiens, or a Neanderthal?” says Tensorer. 
     
    “We expect to find more bones that would help determine what kind of man it was.” 
     
    Humans have been present in what is now modern Syria for 1.5 million years. The area played a key role in the migration of the first human beings towards Asia and Europe, he says. 
     
    Kowm, the site where the remains were discovered along with flint and stone weapons, is a 20 kilometre-wide gap between two mountain ranges that had a number of springs. 
     
    The site was first surveyed in the 1960s and evidence of a 1 million-year-old human settlement has been found there.

  6. Which occipital and lower mandibular skull features are they reffering too as being neandethal indicative?

  7. And this: The puzzle over the relationship between Neanderthals and early modern humans in Western Asia begins with a skull from the Zuttiyeh site in Israel, from a period known as the Middle Paleolithic. The Zuttiyeh skull was associated with an early Middle Paleolithic industry of the Levant region, or eastern Mediterranean, called the Acheulo-Yabrudian. This industry at Zuttiyeh has been dated to as late as 148,000 years before the present (B.P.) (Bar-Yosef, 1998: table 1), but other estimates place the Zuttiyeh skull as early as 200,000 to 250,000 B.P. (Zeitoun, 2001: 522). 
     
    One study has grouped the Zuttiyeh skull with early modern humans (Zeitoun, 2001), but most scientists identify it as archaic. Some think Zuttiyeh was ancestral to the first modern humans of the Levant (Vandermeersch, 1989). Others believe it cannot be clearly linked to any of the later populations of the Levant, either modern or Neanderthal (Stringer and Gamble, 1993: 96). Still others doubt that separate “modern” and “Neanderthal” populations ever existed in this region. In their view, none of the alleged Neanderthals from the Levant had a true Neanderthal morphology as seen in Europe. They see Zuttiyeh as an early member of a single, diverse population that included both the alleged “moderns” and the so-called “Neanderthals” of the region (Arensburg and Belfer-Cohen, 1998: 318-319).

  8. Among two competing theories, the simple and symetric one is preferable. Fine human ladies intermingling with Neanderthal brutes hits me as the more complicated and rather unesthetic alternative. In my guts I feel … whatever.

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