[Taxacom] Homo sapiens neanderthalensis & did early H. sapiens arise in Eurasia?

Kenneth Kinman kennethkinman at webtv.net
Tue Jul 6 00:14:32 CDT 2010


Hi Stephen,
       I suspect that it (the Neanderthal demise) was mainly a
combination of warfare and interbreeding (the results largely based on
the sex of the vanquished).  It was perhaps similar to the later
invasions of Europe which drove the Celts out of most of mainland Europe
and even in the British Isles they were later driven out of most of
England into refuges in Scotland, Wales and Ireland.  Lots of Celts
(especially males) got killed off in the process, but there was also
probably lots of interbreeding with the Celtic widows that survived.                 
       The only difference is that there are substantial populations of
mainly Celtic ancestry still surviving in those outlying areas.  I
suspect that the much earlier battle against Neanderthals, eventually
totally wiped out the male Neanderthals, and a majority of Neanderthal
genes in today's human populations came from modern human males (H.
sapiens sapiens) mating with surviving Neanderthal widows.         
        So in answer to your question, warfare probably wiped out most
of the Neanderthal males over time, but in the case of Neanderthal
females, it was likely more a case of being absorbed by (mating with) a
much larger wave of invading modern male humans.  This might seem like a
bit of a stretch to some, but I believe that the later Celtic example
provides a fairly robust hypothesis for what happened to the
Neanderthals much earlier.  When you have such waves of mainly male
invaders, they had the advantage of both numbers and strength.  The
resident females (especially when widowed) had no power to resist the
inevitable.   
       When it comes to mitochondrial genes passed on through the
females), this would indeed be a major complication for phylogenetics of
such populations.  Less so for non-mitochondrial genes (which pass down
through either sex).  That's why I am even more skeptical about simple
mitochondrial gene phylogenies (without corroboration from nuclear
genes), especially when it comes to humans.  There are no doubt other
taxa with similar histories, but many others are more dependent on
female sexual selection than male dominance.  The mating rules (which
sex dominates in who mates with whom) varies so much between taxa.  Of
course, today a much larger percentage of human females have much more
say in who they mate with, but things were quite different centuries and
millenia in the past.  
        -----------Ken

-----------------------------------------------------
Stephen Thorpe wrote:
Ken, 
What do you think about the theory that neanderthals became "extinct" by
being absorbed through interbreeding with modern humans? This possiblity
raises a general issue whereby two branches of a phylogenetic tree could
perhaps join up to form one. I don't know how much of a "complication"
this would be to phylogenetics? Stephen 
________________________________ 
From: Kenneth Kinman <kennethkinman at webtv.net> 
To: taxacom at mailman.nhm.ku.edu 
Sent: Tue, 6 July, 2010 2:19:13 PM 
Subject: [Taxacom] Homo sapiens neanderthalensis & did early H. sapiens
arise in Eurasia? 
Dear All, 
      When I posted about Neanderthals last week, I failed to
include weblinks to any literature, so before discussing my
classification of Homo sapiens, I wanted to rectify that omission. 
The most recent and important paper discusses the surprising find that
1-4% of the genes in present-day Eurasian human populations came from
Neanderthals.  Since gene flow from the Neanderthals ended with their
extinction 25,000-30,000 years ago, this percentage was no doubt even
higher in the past.  This suggests to me that very significant
interbreeding AND gene flow occurred between Homo sapiens
neanderthalensis and Homo sapiens 
sapiens while they lived together in Eurasia.          
      Anyway, here is a weblink to the abstract of that recent
article in the 07 May 2010 issue of the journal Science entitled "A
Draft Sequence of the Neandertal Genome" : 
http://www.sciencemag.org/cgi/content/abstract/328/5979/710     
          
        There were a number of news stories based on 
these findings and interviews with various anthropologists, including
the following on the BBC: 
http://news.bbc.co.uk/2/hi/science/nature/8660940.stm 
        Below is the subspecies classification which I am still
using for Homo sapiens.  Note that I am still coding H. sapiens
neanderthalensis as evolving from a paraphyletic H. sapiens
heidelbergensis.  If true, the new evidence would also indicate that
H. s. heidelbergensis could have easily interbred with (or even given
rise to) H. s. rhodesiensis.  A slightly different topology might be
that H. s. neanderthalensis split off between H. s. heidelbergensis and
H. s. rhodesiensis, which might further increase the possibility that
the early (archaic) forms of Homo sapiens might have arisen in Eurasia
and then reinvaded Africa before modern humans evolved.  Its
paraphyletic mother species (Homo erectus) could have also originated in
Eurasia. Perhaps Homo erectus floresiensis ("hobbits'") are not so far
geographically from their origins after all.  Anyway, the popular view
of wave after wave of early forms of Homo in just one direction (out of
Africa) might be overly simplistic.  It could be a more complicated
back and forth. 

      Homo sapiens 
             1  H. sapiens antecessor 
             B  H. sapiens cepranensis 
             2  H. sapiens heidelbergensis% 
           _a_  H. sapiens neanderthalensis 
             3  H. sapiens rhodesiensis 
             4  H. sapiens idaltu 
             5  H. sapiens sapiens 

      ---------Cheers, 
                        Ken Kinman 






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