Re: Out of E.Asia II
David Marcus Woodcock (dmw@engin.umich.edu)
4 Nov 1995 04:26:53 GMT
JamShreeve stated:
S>I am puzzled by your contention that your "Out of Asia" theory better
S>fits the evidence than Out of Africa.
That's out of East Asia. [ when I first started thinking about this
idea 15 years ago out of Asia would have been descriptive]
I'll touch on 3 major issues my scenario handles better below:
1] ooa ignores [or attempts to dispute] the fossil evidence of the
erectus-modern transition -- my ooea accounts for it.
2] ooa account of neandertal-H.s.sapiens divergence relies on
no credible isolating mechanism and contradicts fossil evidebce;
ooea agrees with evidence, has an isolating mechanism.
3] ooa relies on a particular interpretation of the genetic data,
however the ooea interpretation fits the data better.
S>The best record for a
S>transition from an erectus-grade form to modern Homo sapiens is in
S>Africa and the Middle East;
I know of no record of transition from erectus to modern found
in Africa or the mideast. I do know of finds described as
modern dated to about 100 kya in S.Africa,Eithiopia and the Mideast.
And I know of much older erectus finds in E.Africa. I don't
know of any finds that appear transitional between the 2 grades
from that part of the world. To my knowledge all the finds
dated between the erectus finds and the 100 kya moderns from Africa
appear to be transitional between erectus and neandertal.
But I'd welcome any references to any finds that do appear to
fit in a series from erectus to moderns.
S>there are no early moderns in Southeast Asia that I know of before
S>60,000 years at most;
The problem is dating fossils older than 50 kya to the nearest
100 kya when there were no convenient nearby volcanos. Wolpoff and
Thorne each have series of skulls that show a smooth progression
from erectus to sapiens ['modern'] grade. They can't point to
the skull next to the last and give it a definite 200 kya date.
S< and the genetic evidence, even without the robust
S>version of "Eve," still consistently favors an African origin over
S>other regions.
As far as I can determine it's the *interpretation* of the genetic
evidence, that favors a recent African origin.
The argument is that there is more genetic variability in Africa,
thus people must have been there longer. There are other
explanations just as plausible. First, note this big
difference in variation holds for quickly changing DNA, eg mtDNA.
Now, even assuming complete replacement of Africans by NE Asians
at 110 kya [ is no assimilation at all the 'robust' version ?]
variation would now be greater in Africa than in NE Asia if there
was a reasonably large sample of NE Asians to start with, and
the population of Africa from 110 to 10 kya was much larger
than the NE Asian population.
A complementary consideration is that my scenario has 2 waves
into Africa [before the current interglacial], with only minor gene
flow out.
And third we cannot rule out a more complex tree for the mtDNA
from the data than is usually presented. Suppose a small
population founded all erectus populations at 2-1.8 mya
[ooea I], then there was gene flow between widely scattered
groups, followed by ooea II about .1 mya -- asians
assimilated smaller groups of africans, and its variants
of mtDNA. I mention this only because there is nongenetic
evidence for this scenario.
Look at Cavalli-Sforza's genetic data in The History and Geography
of Human Genes -- genetic evidence for my ooea I scenario.
And of course, there is the Todaro and Beneviste data and
argument.
S>Admittedly, there may be some evidence of regional continuity in
S>east Asia, though it is certainly disputed (less so in Michigan!).
Proponents must dispute intrepretations that contradict their
theory...but the ooa advocates seem to be reaching a lot when
they reject the multiregionalists' skull series.
S>But in any case, that doesn't mean we've got evidence of eastern
S>hordes sweeping over the west.
More than we have of African hordes sweeping from Africa to
China at 50 kya as I've just heard an out-of-Africa proponent
claim. Why did they pick the worst of the glacial to move
thru the corridor between the Siberian and Tibetan ice sheets ?
Or did they move thru the Burmese jungle -- very quickly
so as to arrive in Australia at 60 kya. :)
[ yes cheap shot. That 50 kya scenario no doubt dates before
the dating of the 60kya Au. material... but it's illustrative
of o-o-a's predictive value -- nihl ]
Of course, I don't think we're dealing with "hordes" at all --
very few people anywhere at 120 kya -- tho I do think
sapiens groups were larger than neandertal ones [ but that's
another post]
--David Woodcock
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