| Thursday,
July 11, 2002 Over on another forum a colleague asks,
"given these revelations that African teachers are giving their
pupils -- male and female -- AIDS, why did we not hear about their making
the girls pregnant prior to the outbreaks of AIDS?
My guess is that this has little to do with AIDS and a lot to do with
timing. Meanwhile, "Where is the Ten Billion Dollars?"
In a power setting like a school you get one result; but in a system of
reasonably free choice, surely AIDS is one of the easiest maladies to
avoid? I know if I were addicted to drugs I would like to think I'd be
rational enough to acquire a case of diabetes needles and always use my
own. I might give one to a friend but I wouldn't want it back.
Microsoft is changing its corporate fee structure. I presume all
readers who need to know about this already do:
http://www.theregister.co.uk/content/4/26141.html
And Roland finds more vulnerabilities in Outlook and Internet Explorer:
http://www.pivx.com/larholm/adv/TL003/
as well as SQL
http://www.theregus.com/content/4/25563.html
How old is the human race? And did we come OUT of Africa or INTO
Africa?
http://www.rafonda.com/age.html
Age and Origin of the Human Species
The speciation event
that produced Homo sapiens sapiens could not have occurred
contemporaneously in more than a very few individuals. It follows that
those few s. sapiens would have possessed a very restricted sample of the
progenitor species' genetic diversity. However, the diversity observed in
current populations implies that there were never less than several
thousand breeding pairs in the human ancestry (Harpending et al., 1998).
Accordingly, the founding s. sapiens and their descendants must have
interbred with the progenitor species (and perhaps other pre-human
populations) in order to preserve the diversity which exists today.
While some changes
in the genome must have occurred after the speciation event, the
"lifetimes" of the genetic elements considered (in this context
and the works cited here) are far longer than new estimates of s. sapiens'
age (Mountain et al., 1994). As a consequence, most of the current
diversity must be the result of interbreeding with pre-human
populations. On this view we would expect to see the most hybridized
elements of the modern indigenes in those areas where pre-human population
density was highest, such as Africa and S. E. Asia. Also, we would expect
those populations to have the greatest diversity today, because they would
preserve more of the pre-human genome, which would have had much more
genetic variety than was represented in the tiny, original population of
s. sapiens.
In fact, we do
find that Africans and some S. E. Asian populations have not only more
diversity (Jorde et al., 1997), but central Africans are said to have
ancestral genetic elements as well (Tishkoff et al., 1996). It is also
clear that the population which gave rise to s. sapiens had been separated
from the sub-Saharan Africans' ancestors for longer than our species'
lifetime.1 This requires the proponents of the "African Eve/Out of
Africa" views to posit a segregation of central Africans from the
proto-modern population in which speciation occurred. Since they also
claim that modern humans originated in and radiated from Africa, Tishkoff
(for instance) is driven to suggest that this hundreds of thousand year
sequestration was somewhere in N. E.
Africa.2 This is an implausible, ad hoc
suggestion. By contrast, it is natural to suppose that separation implies
the population ancestral to humans was a part of the radiation out of
Africa into Eurasia, before the speciation event occurred. If the
speciation event took place in Eurasia, we would expect that the
descendant population would show a "bottleneck" effect, and that
those populations would possess low genetic diversity today, relative to
central Africans, which is what we find.3
< snip >
Discussion in Mail
TOP
Current Mail
|
CLICK HERE for
a Special Request. 
