In a commentary accompanying the Green et al. paper in Cell, Andrew Clark of
Cornell mentioned several interbreeding scenarios still consistent with the
new mtDNA sequence data; eg if all matings were between Neanderthal males
and modern human females, since mtDNA is transmitted only on the maternal
line, such matings would lead to admixed nuclear DNA but no Neanderthal
mtDNA in the offspring and their descendants (down to the present day.) The
overall evidence is leaning against significant interbreeding, but the full
Neanderthal nuclear sequence, due later this year, should provide much more
information about that.

This Wikipedia entry is very confused and incorrect at the end when it talks
about farmers and the Middle Stone Age (MSA). The MSA is a term used only
for Africa; in Eurasia the corresponding period is the Middle Paleolithic.
which corresponds to Neanderthal habitation. And farmers from the Near East
entered Europe (or the idea of farming did, this is the demic diffusion vs
cultural diffusion debate) only during the Neolithic period (beginning
around 8500 years ago in Europe), and not during the Middle Paleolithic,
Upper Paleolithic, or even the Epipaleolithic (called Mesolithic in Europe)
periods that preceded the Neolithic.


On Wed, Aug 13, 2008 at 8:07 AM, Jim West <[log in to unmask]> wrote:

> Here is an Wikipedia article.
> Heritage, the interbreeding controversy, and brain capacity are described.
> Jim West
> ======
> On November 16, 2006, Science Daily published an interview that suggested
> that Neanderthals and ancient humans probably did not interbreed. Edward M.
> Rubin, director of the U.S. Department of Energy's Lawrence Berkeley
> National Laboratory and the Joint Genome Institute (JGI), sequenced a
> fraction (0.00002) of genomic nuclear DNA (nDNA) from a 38,000-year-old
> Vindia Neanderthal femur bone. They calculated the common ancestor to be
> about 353,000 years ago, and a complete separation of the ancestors of the
> species about 188,000 years ago. Their results show the genomes of modern
> humans and Neanderthals are at least 99.5% identical, but despite this
> genetic similarity, and despite the two species having coexisted in the
> same
> geographic region for thousands of years, Rubin and his team did not find
> any evidence of any significant crossbreeding between the two. Rubin said,
> "While unable to definitively conclude that interbreeding between the two
> species of humans did not occur, analysis of the nuclear DNA from the
> Neanderthal suggests the low likelihood of it having occurred at any
> appreciable level."
> A main proponent of the interbreeding hypothesis is Erik Trinkaus of
> Washington University. In a 2006 study published in Proceedings of the
> National Academy of Sciences, Trinkaus and his co-authors report a
> possibility that Neanderthals and humans did interbreed. The study claims
> to
> settle the extinction controversy; according to researchers, the human and
> neanderthal populations blended together through sexual reproduction.
> Trinkaus states, "Extinction through absorption is a common
> phenomenon."[35]
> and "From my perspective, the replacement vs. continuity debate that raged
> through the 1990s is now dead".[36] 4 amino acid substitutions in mtDNA
> translated changed COX2 protein[37] of Cytochrome c oxidase subunit II.
> Recently, Richard E. Green et al. from Max Planck Institute for
> Evolutionary
> Anthropology published the full sequence of Neanderthal mitochondrial DNA
> (mtDNA) and suggested that "Neandertals had a long-term effective
> population
> size smaller than that of modern humans." [38] While reporting in Nature
> Journal about the same publication, James Morgan asserted that the mtDNA
> sequence contained clues that Neanderthals lived in "small and isolated
> populations, and probably did not interbreed with their human neighbours."
> [39]
> There is a possibility Neanderthals and Cro-Magnons interbred but left
> little genetic evidence. There is an ongoing debate about whether the
> hunter-gatherers of the middle stone age started farming when they came in
> contact with agriculture, or were completely replaced by the farmers moving
> in from the Middle East. If modern Europeans are mainly descendants of
> these
> farming people with little or no genetic input from the foragers of the
> middle stone age, then possible interbreeding between them and the
> Neanderthals would not have had a great effect on the modern gene pool.[40]

Michael Balter
Contributing Correspondent, Science
Adjunct Professor of Journalism,
Boston University

Email:           [log in to unmask]

Balter's Blog: