Re: Linguistic Challenge for John the "geneticist"

Tommy Tyberg wrote

> I am perfectly aware that the human species is remarkably homogenous

from a

> genetical point of view, probably mostly because we are an extremely

young

> species (200-300,000 years?).

Tommy do you have any evidence of Homo sapiens from such a depth. I am
only aware of H.sapiens from Klassies River and other sites in South
Africa from about 130-150,000 years. This seems to accord best with
the genetic evidence for the date at which human species began to
diverge too.

> The biologically interesting question is how
> (and why) such a young species has become so strikingly polymorphic

in such

> a short time, for not only are humans divided into races but these

races

> are remarkably different in appearance, more so as a matter of fact,

than

> for most polymorphic species.

These races are very different to humans who see the differences as
ways of assessing "us" versus "them". For a species that is young and
of global provenance, we are no more polymorphic than any other
creature.

Part of the explanation of the "polymorphic nature" is due to the fact
that until comparatively "modern times" there was little travel between
human communities over long distances, and we were talking about only
3-10 million humans 12,000 years BP, so possibilities of genetic drift
and accute selection pressure could easily apply.

> In part these differences are certainly adaptation to physical

conditions,

> many of the traits characteristic for australian aborigines being for
> example obvious adaptations for life in in a hot, arid environment

with

> strong sunshine, but I am fairly sure that this is not the whole

story.

> There is strong genetic evidence that the human species has passed

through

> at least one fairly narrow population bottleneck in the past. If this
> involved several small isolated populations some differences may

simply be

> due to random genetic drift. A perhaps more likely explanation is

sexual

> selection, since this is known to able to cause striking differences

in

> physical appearance between very closely related taxa, such as Birds

of

> Paradise or Ducks.
>
> Finally I can't see what is wrong with using subspecific differences

to

> reconstruct patterns of migration. This is done all the time in

zoology.

> Nobody accuses me of racism if I claim that the Yellow Wagtails with

yellow

> heads that have started to breed in southwestern Norway in the last

few

> decades originally immigrated from Great Britain since they clearly

belong

> to the (british) flavissima subspecies, indeed everybody regards this

as

> self-evident. Certainly thorough genetic analyses are better, but

they are

> also much more difficult to perform, and the data is usually just not
> available.

And since it is real embodied human beings (complete with genes and
culture) who speak languages, such patterns of migration are likely to
have a huge influence on linguistic distibution.

Thanks Tommy for your support in the debate between the "use a wide set
of evidence to discuss paleoethnography" (eg Alexander, myself and now
you) versus the position of Glen the pure linguist who denies the
relevant evidence from any other source of data than linguistic in
looking at the human origins de la parole.

Best wishes

John