genetic facts [was: Ashby, botanical facts

Peter Ashby p-ashby at nimr.MAPS.mrc.ac.uk
Wed Oct 7 13:19:43 EST 1998


In article <6vdl79$fdd$1 at whisper.globalserve.net>, yuku at globalserve.net
(Yuri Kuchinsky) wrote:

> Peter Ashby (p-ashby at nimr.MAPS.mrc.ac.uk) wrote on 5 Oct 1998 21:03:48 GMT:
> 
> : 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 I have such evidence.

Sorry Yuri, I should have said 'any GOOD evidence'. My apologies for the
inaccuracy.
 
> : > 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.
> 
> How so?
> 
> : 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.
> 
> Obvious red herring. I have to do no such thing.

Yuri, yet again, in order to use the absence of a genetic feature as
evidence for relatedness between two geographically separate populations
it is necessary to show that some thing operated which precludes at least
one of the events being due to some (any) form of genetic drift.  See J.R.
Pelmont's excellent post earlier today or yesterday for a detailed
explanation of how easy it is to change blood groups by genetic drift.

How about on this one you admit defeat Yuri. I count three or four posters
who have pointed out to you from positions of knowledge that Blood groups
are unreliable and only you in favour.

You will also not that the mtDNA evidence is based on the possession of a
feature which is not open to the sort of genetic drift you seem unable to
understand and Has the advantage of being measurable in archeoological
samples.

> : 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
> 
> Correct, but this does not contradict Heyerdahl.
> 
> : and none with north america (where Yuri proposes they
> : originated).
> 
> You're being dishonest again now. This is false.

Which is false? that there is no mtDNA evidence for north america as
origin or that you propose the polynesians originated there?
 
> : 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.
> 
> And what about another study that supported Heyerdahl? Did you
> conveniently forget?

Yuri, that was the study you think supports Heyeredahl. Although if Thor
is right you would expect a much higher level of south american features
which we don't find.
 
> : If
> : Heyerdahl were right you would expect a much higher incidence of south
> : american features in polynesian DNA.
> 
> But we do have them...

Sorry again Yuri, I should have said mtDNA. And there is an extremely smal
incidence of such features, and this does not support Heyerdahl, at least
as you portray and quote him. Are you know saying that you have
misrepresented the great man's ideas?
 
>         ...
> 
> : > 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 claim no special expertise in genetics. But at least I'm honest, and I'm
> willing to learn new things.

You have demonstrated no such willingness. Yuri, learning new things must
always involve a willingness to change your world view in the light of the
new things. your pattern however is to take the new thing and if you can't
twist and mutate it into something supporting Heyerdahl you attack it.  I
was prepared to entertain your notian that early polynesians didn't have
the chicken until the original table of data was posted here a couple of
years ago showing that your statement of absence of chicken from the
oldest layer to be a gross over interpretation of the data.
 
> : I repeat I
> : am NOT postulating any extraordinary events,
> 
> But you do.
> 
> : that is your particular spin
> : on what I said.
> 
> And here you sort of admit it...
> 
> : I am merely pointing out that your precious blood group
> : data is unsafe a as a measure of relatedness
> 
> I'm aware of some of its limitations.

An admition! hallelujah, praise the Lord (Thor). So do tell me the
limitations of blood group data as you perceive them.
 
> : 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.
> 
> False. They are certainly subject to genetic drift. But this drift is not
> entirely unpredictable and is subject to well-understood processes. Group
> B can not disappear so easily.

See again, J.R. Pelmont's most knowledgeable post about how easy this is.
If you don't uderstand it I will be happy to explain it to you.
 
> : Yuri, what you have proposed is untestable as I have explained to you as
> : blood groups do not survive in the fossil record.
> 
> This is questionable. I believe old mummies can be tested for blood groups
> to some extent. You seem to be wrong about this.

Belief is not evidence Yuri. References please for reliable blood group
data from mummies.
 
> : Accordingly what you
> : have proposed is not a scientific hypothesis since it is not subject to
> : experimental refutation.
> 
> False.
> 
> Also, there are many problems with extracting ancient DNA from skeletons
> as well. Your "expert" analysis of this matter seems to be lacking.

I am well aware of the problems inherent in extracting dna from anything
Yuri. I have suffered more than once from contamination in PCR
experiments. The problem you have Yuri is that if contamination was
happening on a large scale the mtDNA evidence would imply relatedness to
all sorts of people. In case you aren't aware of it, good scientists do
controls to rule out such things. See the paper from nature on mtDNA
extraction from neanderthal bones for what is possible.
 
> : Yuri, If you haven't understood the mtDNA evidence posted so far then I
> : cannot be held responsible for your failings of understanding.
> 
> There's no problem with my understanding. OTOH there seem to be many
> problems with both your competence and objectivity in this matter, and
> with your obvious bias against Native Americans. Why didn't you reply when
> I asked you to clarify your biased opinions about them?

yuri, I hate to pull rank on you but I have very good credentials in this
field and you apparently have no credentials in any field. So if you want
to imply that I am incompetent in the field of DNA you had better be able
to prove that your own is better. I am waiting, MISTER Kuchinsky.

> : Am J Hum Genet 1996 Jul;59(1):253-258  
> : Lack of ancient Polynesian-Amerindian contact.
> : Bonatto SL, Redd AJ, Salzano FM, Stoneking M
> 
> Well, thank you. So how about this then, from the very same issue of Am J
> Hum Genet?
> 
> Mitochondrial Myopia: Reply to Bonatto et al., R. L. Cann and J. K. Lum
> 
> So here you go, my poor confused friend. You've lost another one...
> 
> : If this doesn't contratdict Heyerdahl in plain English
> 
> No it doesn't, really, in whatever language you may wish to translate it
> into.
> 
> You're very confused, and also quite uninformed Peter. Obviously you don't
> have anything more to offer here than your one bare ref. Have you read
> that article you gave the ref for? Somehow I doubt it. You just love to
> appeal to authority, right? How scientific...

Yuri, next time you go walking in usenet land, keep a better eye open for
traps. You said that there was no mtDNA evidence which contradicts
Heyerdahl. The reference I posted is just such evidence. Your reaction to
it is a classic example of the fact that you don't understand the nature
of scientific evidence. I never claimed that it was conclusive proof. I
never claimed that it was GOOD evidence,  The data I discuss earlier in
this post contradicts it. The point is that is evidence against heyerdahl,
that is however all it is. Maybe one day you will understand the
difference between evidence and proof. 

> Now, what is the real situation with all this latest mtDNA stuff? Actually
> this evidence is entirely consistent with Heyerdahl, and supports him to a
> significant extent.
> 
> Rebecca L. Cann and J.K. Lum are the scholars who are supporting
> Polynesian -- American links recently based on DNA. They have studied the
> DNA of living Pacific populations and compared their findings to the DNA
> of native Americans. They found that several mitochondrial DNA lineages
> occur both in the Pacific area and among Amerindians.
> 
> Bonatto et al. actually AGREE with Cann & Lum on this. So this is very
> significant. 

Yuri, I can make no judgement from this. References please. Title,
Journal, date, volume, page number.
 
> 
> And thus, your game is up, Peter. Certainly the latest DNA finding cannot
> be seen as contradicting Heyerdahl. Supporting him is more like it. 

Yet again you demonstrate your fundamental misuderstanding of the nature
of evidence and proof. You even admit yourself that they can be
interpreted in more than one way. I really am almost ready to give up on
you. I originally entered this debate because you cross posted to
soc.culture.new-zealand and your use of science was so appalling I
couldn't let it pass. I thought (naivly) that I could point out the error
of your ways and improve your reasoning. It is obvious that my mission has
been doomed from the start. There are none so blind as them who will not
see.
 
Yours pessimistically

Dr. Peter Ashby

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

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