GENEALOGY-DNA-L Archives

Archiver > GENEALOGY-DNA > 2006-05 > 1147709123


From: "Ken Nordtvedt" <>
Subject: Re: [DNA] RE: Amazing article about genetics -- please help
Date: Mon, 15 May 2006 10:05:23 -0600
References: <032301c67833$c3395ee0$6401a8c0@Precision360>


Lawrence,

Your first point is even more powerful when it is realized that each
chromosome just breaks up into a small number of pieces (I heard about 3),
and then those pieces recombine as a whole each generation. I estimated
that further back than about 10 generations, because the number of ancestors
contributing to our actual genes only grows arthimetically rather than
exponentially, more and more of those "ancestors" are only behavioral
ancestors via their matings, and they actually contribute to none of our
genes.

I think that's why as we go back in time my interests divert to following
the history of the contributory tribes to my being, since it is those tribal
gene pools which become relevant in deep ancestry.


----- Original Message -----
From: "Lawrence Mayka" <>
To: <>
Sent: Monday, May 15, 2006 9:25 AM
Subject: [DNA] RE: Amazing article about genetics -- please help


>> From: [mailto:]
>> states that "it is no exaggeration to say that it is likely
>> that every person
>> of Northern European descent is a descendant of
>> Charlemagne...". He believes
>> that on average all people alive today are as genetically
>> similar as third
>> cousins. It also appears that he believes we are all pretty
>> inbred. There is
>> much more in this four part series that intrigues me. Also,
>> he states in the
>> final topic that it is possible to have inherited more
>> genetics from one gender
>> than the other (please see final paragraph).
>
> I agree with others that the series of articles is rather poorly written,
> and certainly rather out-of-date.
>
> 1) The argument of exponentially increasing ancestors is a fallacious one,
> for two reasons.
>
> A) The human genome has only about 25000 functional genes. This means
> that
> beyond about 15 generations back, many 'ancestors' are mere phantoms, who
> have not contributed a single gene to the descendant's genome. Such
> 'ancestry' is meaningless in both science and practice. There is a good
> reason that genetic genealogy focuses on the strict patrilineal and
> matrilineal lines: Because beyond 15 generations, only those two lines
> have
> provably contributed a significant number of genes to the descendant's
> personal genome.
>
> B) The author greatly underestimates the restricting influences of
> residency, culture, religion, and social class. Charlemagne was a Western
> European Frank, a Catholic, and an emperor. It is highly unlikely that he
> is even a 'phantom' ancestor of every single Saami and Roma, every single
> Jew and Russian Orthodox, and every single peasant (descendant of serfs)
> in
> northern Europe. Such a wild generalization, without a whit of proof and
> with all evidence to the contrary, greatly misleads rather than enlightens
> the public.
>
> 2) His argument of universal inbreeding is a rather backward way of
> explaining a well-known phenomenon. Science has shown that the genetic
> differences across the human race are so minor that even a small community
> has most of the diversity of the entire race within it. In other words,
> genetics simply agrees with anthropology that even a small human community
> maintains sufficient genetic diversity to survive for thousands of years
> without fatally succumbing to the genetic defects usually associated with
> 'inbreeding'. Another way to say this is that the marriage of second or
> third cousins is no cause for concern at all, and even the marriage of
> first
> cousins can often bring as much good as harm, if the bride and groom are
> carefully matched to encourage characteristics appropriate to local
> conditions (the same way one might breed horses or dogs). Not that I
> personally recommend the subordination of human marriage to such goals. ;)
>
> 3) His argument of unequal numbers of male and female ancestors does not
> imply inheritance of more genes from one or the other gender. The more
> cogent argument is that, of the 25000 genes in a descendant's personal
> genome, it is impossible to know how many of those genes actually came
> from
> male vs. female ancestors. Reportedly, genetic crossover simply performs
> too much shuffling for anyone to track.
>
>
>
> ==============================
> Search the US Census Collection. Over 140 million records added in the
> last 12 months. Largest online collection in the world. Learn more:
> http://www.ancestry.com/s13965/rd.ashx
>
>



This thread: