genetic facts [was: Ashby, botanical facts

Peter Ashby p-ashby at nimr.MAPS.mrc.ac.uk
Mon Oct 5 16:03:48 EST 1998


In article <6varkn$as1$1 at whisper.globalserve.net>, yuku at globalserve.net
(Yuri Kuchinsky) wrote:

> Gerard Tromp (tromp at sanger.med.wayne.edu) wrote on Sun, 04 Oct 1998
17:51:01 -0400:
> : Yuri Kuchinsky wrote:
> 
> :       Could someone please summarize, succinctly, the genetic data in these
> : arguments.
> 
> Dear Gerard,
> 
> I repost my summary further on.
> 
> The discussion about Heyerdahl's hypothesis re: human settlement of
> Polynesia has been going on forever in sci.arch. There are many hundreds
> of posts. Plenty of other evidence has been brought forward to back it up.
> Especially the hypothesis about Easter Island to S America links has now
> been basiclly confirmed. The best substantiation is botanical, but there's
> a lot more of course, such as similar art styles, architecture,
> ethnographic support, etc.

If the best substantiation is botanical then all you have is evidence for
contact at some time by some one. You do not have any evidence for the
link being driven by south americans.
 
> But the discussion of the genetic evidence is still quite new to us in
> sci.arch.
> 
> : On the one hand we have some reference to a low
> : representation of B blood groups (genetic isolates tend to have these
> : biases),
> 
> This may be so. But in this case, do we assume that the Polynesians, and
> the Native Americans are _both_ genetic isolates? Is such an assumption
> justified?

yes Yuri it is. In order to argue against this you have to suggest some
mechanism by which both polynesianss and native americans manage to absent
themselves from the environmental influences and genetic drift which
affects all forms of sexual life on this planet. Or are you going to get
even worse and propose that they are aliens?

> : on the other some mtDNA evidence that I seem to have missed
> : (perhpaps my newsfeed did not pick it up).
> 
> Well, Ashby did post something in sci.arch a while back. It is up to him
> to summarize that evidence briefly. Why should I do his work for him?
> Since that evidence hardly supported his extreme claims, perhaps that's
> the reason he's slow to summarize it?

I have been a bit slow Yuri because unlike you I have a job in science to
do. I am moving to Scotland in 2 months and am rather pushed for time. I
did a search in the PubMed reference database on the keywords: polynesian
and DNA. I got about a dozen references, the vast majority using mtDNA
analysis. The vast majority also found that polynesians show most affinity
with south east asia and none with north america (where Yuri proposes they
originated). One study found a  very low level of a south american feature
(2 in 1,780 IIRC) which supports some sort of contact between South
America and polynesia. It does NOT support Heyerdahl's contentions. If
Heyerdahl were right you would expect a much higher incidence of south
american features in polynesian DNA.
 
> : What comprised the mtDNA
> : data? What were the conclusions from the mtDNA data (I infer that it
> : provides a link to the Asian population rather than that of the
> : Americas). 
> 
> Your inference is correct. But this data certainly did not contradict
> Heyerdahl's hypothesis.

See above.
 
> :       We seem to be getting an awful lot of hot air about this. As has been
> : pointed out, allele frequencies at a particular locus are rather poor
> : evidence of relatedness due to fluctuations over the time spans
> : involved,
> 
> Well, maybe I don't have the best evidence of relatedness on my side. But
> I maintain that what I have is better than what he has.

Ok Yuri, so you don't have the best evidence (interesting admission, must
save this), and according to you I don't (or rather PubMed doesn't). So
who does have the best evidence then? do tell Yuri I am most interested to
know.

> : one would have to take frequencies from a whole array of
> : nuclear genes into consideration to ensure that selection at a given
> : locus was not influential. Even then founder effects _could_ play havoc
> : with the outcome when comparing distant relationships  in a pairwise
> : manner (i.e. over long periods of time), and without intermediate data.
> 
> Sure, the founder effect needs to be considered. But, again, we are
> postulating two extraordinary events (i.e. the loss of group B genes
> happening twice in two populations) that are also supposed to be entirely
> _unrelated_? This does not seem too easy to accept.

Only to someone like you who has demonstrated a distinct lack of
understanding of genetics in particular and Biology in General. I repeat I
am NOT postulating any extraordinary events, that is your particular spin
on what I said. I am merely pointing out that your precious blood group
data is unsafe a as a measure of relatedness since ALL populations are
subject to genetic drift (of which I gave some examples) and to postulate
relatedness Yuri has to explain why these two populations would not be
subject to it.
 
> : As has also been pointed out, mtDNA evidence tends to be more useful for
> : establishing distant relationships since it is prone to fewer selective
> : pressures (most of the selective pressures occurred during the
> : developement of early eukaryotes when mitochondria lost a number of
> : genes whose function was assumeed by nuclear genes, leading to a rather
> : minimal, asexual genome), and is transmitted linealy without
> : recombination from mother to offspring.
> 
> Sure. But mtDNA evidence that disproves Heyerdahl seems to be conspicuous
> by its absense so far.
[SNIP] more old blood group refs and quotes from the holy book of
Heyerdahl. Yuri, yet again, repetition is no substitute for argument.
 
> This should confirm that Polynesians spread out from America. This
> evidence suggests that Polynesians acquired these groups in a small way
> later through intermarriage with Melanesians. In Samoa, B is actually
> quite high. So my (Heyerdahl's) hypothesis accomodates this evidence very
> easily indeed. On my hypothesis, Polynesians did not have B in their
> homeland (British Columbia), and then acquired it later after arriving to
> Western Polynesia.

Yuri, what you have proposed is untestable as I have explained to you as
blood groups do not survive in the fossil record. Accordingly what you
have proposed is not a scientific hypothesis since it is not subject to
experimental refutation.
 
> So what Ashby would need to explain is how his hypothesis, if he has one,
> would accomodate the existing evidence for group B distribution throughout
> Polynesia, i.e. absense of group B in the Eastern Polynesia, and the
> increase of group B in the Western Polynesia. Did the Polynesians continue
> to lose B factor gradually as they were approaching the American
> continent? But this is impossible and is beginning to sound ever more like
> Psychic Science. The neck of your bottle is beginning to look awful wide
> here, Ashby...

See above, but then you will never accept anything which conflicts with
saint Thor's world view will you Yuri? it is really quite sad that you
can't break free from someone else's opinions and form and defend a
position of your own. this is what happens when a real scientist matures
and breaks away from their supervisor. Strike out on your own Yuri, open
your eyes and you might just enjoy the world a bit more. There is plenty
of argument to be had without having the whole world against you, you
know.
 
> And also of course Ashby would need to provide some sort of a model for
> why the American Indians are also lacking group B. Good luck!

I don't have to Yuri, as I have pedantically explained to you. You have to
explain why both groups should be absented from nature.
 
> However much he tries, Ashby cannot sweep all this valid scientific
> evidence under the rug.
> 
> So this is my positive evidence.
> 
> Now, on the other side of the ledger, if Ashby wants to make some sort of
> a valid case for the mainstream dogma, he would need to provide what I've
> asked him repeatedly, and what he failed to provide so far. 
> 
> No, thank you, my memory is just fine. It is Ashby's memory and commitment
> to scientific method that are lacking. Because so far he COMPLETELY FAILED
> TO PROVIDE any recent mtDNA evidence WHATSOEVER that would invalidate
> Heyerdahl. I'm still waiting.
> 
> So where is any mtDNA evidence that goes against Heyerdahl? The only thing
> that Ashby provided so far is some evidence linking Polynesians with South
> China area, and showing that they may have ultimately derived from that
> area ca. 5000 years ago. But, as I've explained repeatedly, this does not
> really contradict Heyerdahl.

Yuri, If you haven't understood the mtDNA evidence posted so far then I
cannot be held responsible for your failings of understanding. I might
feel sorry for a student who just can't get to grips with the material but
that doesn't stop me failing them. Carping on that you don't get the
evidence which others have no trouble seeing is quite pathetic.

in refutation I will repost one reference. I will not post them all as
anyone with web access and half a brain can look them up themselves using
the same keywords. Anyone without web access is welcome to email me for
the list. there has been enough bandwidth wasted on Yuri's misconceptions
already.

Am J Hum Genet 1996 Jul;59(1):253-258  
Lack of ancient Polynesian-Amerindian contact.
Bonatto SL, Redd AJ, Salzano FM, Stoneking M

If this doesn't contratdict Heyerdahl in plain English then Yuri is about
to be offered a professorship of genetics at Harvard. I look forward to
attending his inaugural seminar.

Peter

-- 
Peter Ashby
Eukaryotic Molecular Genetics
Nat. Inst. Med. Res.
London

Reverse the spam and remove to email me.



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