>What about those human individuals who have Neanderthal features,
>in the skull or the posture? What are we to think of those, under
>the new view suggested by recent DNA work?
The mtDNA work only ruled out that that particular Neanderthals mother (and
her female relatives) left no offspring. But even if we have no maternal
mtDNA from the Neanderthal, we very well might have nuclear DNA from them.
Neanderthal jaws had a wierd form of the mandibular foramen. This is the
place where the dentist tries to inject the novacaine to deaden your nerves.
The mandibular foramen is where the nerve enters the jaw. Anyway, 53% of
Neanderthals had the H-O form of this feature. 47% had foramens like most
modern humans. No other skeletons on earth at the time of the neanderthals
show the H-O foramen--I stress that only Neanderthals had it. Neanderthals
were restricted to Europe and its immediate environs. Anatomically modern
fossils from Africa and Asia have 0% H-O foramens. Yet in the early upper
paleolithic 18% of the anatomically mdoern people had the H-O foramen. This
had dropped to 7% among the late Upper Paleolithic anatomically modern
people. Today only about 1% of modern Europeans have the H-O foramen.
Today, no Africans nor Asians have this peculiar feature. Where did the
modern EUROPEAN humans get this feature? I would contend that it came from
the small amount of interbreeding between the Africans invading Europe and
the indigenous Neanderthals. Neanderthal genes were swamped by the influx
of anatomically modern humans but there are still some of their genes
residing in modern Europeans (in particular the gene for the H-O mandibular
foramen). There are other Neanderthal traits that are also localized to
modern Europeans.
How does this happen? There is a phenomenon calld crossover in which part
of your mothers chromosome will switch with the homologous part of your
father's chromosome. Because of this, the lineage of nuclear DNA cannot be
determined.
Take a chromosome during cellular division. The cell starts with 2 copies
one from the father one from the mother.
Chromosome pair in original cell (M is from mom and F is from father)
FFFFFFFFFFFFFFFFFFFF
MMMMMMMMMMMMMMMMMMMM
Each chromosome must duplicate at cell division time so it looks like
FFFFFFFFFFFFFFFFFFFF
FFFFFFFFFFFFFFFFFFFF
MMMMMMMMMMMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMM
But then occasionally crossover occurs and we now have
FFFFFFFFFFFFFFFFFFFF
FFFFFFFFFFMMMMMMMMMM
MMMMMMMMMMFFFFFFFFFF
MMMMMMMMMMMMMMMMMMMM
The first and third chromosomal copies go to one cell and the 2nd and 4th go
to another. The daughter cells look like
Daughter cell 1
FFFFFFFFFFFFFFFFFFFF
MMMMMMMMMMFFFFFFFFFF
Daughter cell 2
FFFFFFFFFFMMMMMMMMMM
MMMMMMMMMMMMMMMMMMMM
When this occurs in the stem cells for sperm and egg one can pass
neanderthal genes widely into a population even if there is only limited
interbreeding.
And because of crossover, the original authors of the Neanderthal mtDNA
article which ruled out that Neanderthal from having left a maternal
inheritence to modern people. They admit (although many Christian apologists
and African Eve advocates won't):
"These results do not rule out the possibility that
Neandertals contributed other genes to modern humans. However,
the view that Neandertals would have contributed little or
nothing to the modern human gene pool is gaining support from
studies of molecular genetic variation at nuclear loci in
humans."~Matthias Krings, et al., "Neandertal DNA Sequences and
the Origin of Modern Humans," Cell, 90:19-30, p. 27
If future work rules out any neanderthal contribution to modern humanity, it
still doesn't rule out them as being human. The Viking Greenlander
colonists all died without leaving offspring in the modern world also, yet
the Pope was very concerned about their spiritual well being. However, that
future work must explain how Europe seems to produce people with the very
rare H-O mandibular foramen in their jaws.
reference
David W. Frayer, "Evolution at the European Edge: neanderthal and Upper
Paleolithic Relationships," Prehistoire Europeenne 2:9-69, p. 29
glenn
Adam, Apes, and Anthropology: Finding the Soul of Fossil Man
and
Foundation, Fall and Flood
http://www.isource.net/~grmorton/dmd.htm