I'm not sure if I understand either the argument below or in the cited
Native American Inheritance Chart , however:
(1) Would this not also be the case --- if it is the case --- not just in
the Native American example given, but for any genetic inheritance.
According to this argument, as I understand it, after a certain number of
generations one would no longer carry any genetic inheritance ("markers")
from earlier generations. If this were the case, and it we accept the idea
that genealogy = DNA, then it would become irrelevant to search one's
ancestors beyond some critical number of generations. Not that the
intuitive is necessarily correct, this does not seem to make sense.
(2) I am --- like apparently half of Virginia --- a distant descendant of
Pocahontas, among many others. Far less than 1/16th. To me this is not only
a matter of DNA, but also history and culture. If this were not the case,
genealogy would be of little interest to me, and I suspect many others. For
me, genealogy is many things, including a way of understanding myself, my
family and my society.
St. George Tucker Ranson
At 11:42 AM 11/4/2003, Lee Anne Center wrote:
>I'm forwarding this from another list because it is an interesting question.
>
>Lee Anne
>
>----- Original Message -----
>From: "Dale Marr" <[log in to unmask]>
>To: <[log in to unmask]>
>Sent: Monday, November 03, 2003 9:54 PM
>Subject: [ARIZARD-L] Genetic Testing
>
>
> > > I have a dumb question I hope you will take the time to answer. If a
> > distant ancestor were only like 1/16 Indian, would that reduce by each
> > generation until there were no markers, or are the original genetic
> > markers there forever?
> >
> > My first thought was that this thread should be labeled "off topic," but
>if you think about it genetics is the very foundation of genealogy. It's
>not a dumb question at all. It sounds like a logical conclusion at first
>glance, but the different types of markers (in the case of American Indian
>testing, mtDNA and Y-chromosome) don't get "reduced" in each generation.
>I'm certainly no authority, but this is the way I understand it.
> >
> > Y-marker testing is done for the markers on the Y chromosome (and
>obviously only on males). This chart shows four generations of males. As
>you can see each male child gets all the information on his Y chromosome
>from his father who got all the information from his father and so on....
>It doesn't get "diluted" from one generation to the next just like the ABO
>blood types don't dilute. (Determining blood types of your ancestors is
>kind of interesting, too.) Humans have 22 other pairs of chromosomes with
>all kinds of information that does get diluted.
> >
> > XX=female, XY=male
> >
> > 1 XY + XX
> > . | |
> > . -------
> > . |
> > 2 XY + XX
> > . | |
> > . -------
> > . |
> > 3 XY + XX
> > . | |
> > . -------
> > . |
> > 4 XY
> >
> > MtDNA testing is done on a male or female at the end of a female-to-female
>line. Mitochondrial DNA (mtDNA) is a different kind of DNA from that in the
>nuclei of cells. It's in the mitochondria, those little thingies that
>supply energy to the cell. You have the same "set" of mtDNA as your mother,
>your maternal grandmother, your maternal grandmother's mother, and so on....
> >
> > This chart shows four generations of females. Though a female gets an X
>chromosome from each parent, and a male gets an X chromosome from his mother
>and a Y chromosome from his father, each gets ALL his or her mtDNA from the
>mother. The male doesn't pass along any mtDNA, represented by the lower
>case "m", to his children. Rather his children get all their mtDNA from
>their mother who got it from her mother, etc. If you follow the upper case
>"M" in each generation and think of that as a "package" containing the mtDNA
>(oversimplified but illustrates the point), you can see it doesn't get
>diluted as it's passed to each generation.
> >
> > 1 MXX + mXY
> > . | |
> > . -------
> > . |
> > 2 MXX + mXY
> > . | |
> > . -------
> > . |
> > 3 MXX + mXY
> > . | |
> > . -------
> > . |
> > 4 MXX
> >
> > This is another site that has a lot of information and a much better chart
>than I can draw here. http://www.familytreedna.com/tcnam.html Of my two
>charts above, the first one corresponds to the blue line and the second one
>corresponds to the red line in their complete chart.
> >
> > Dale
> >
> >
> >
> >
> >
> >
> >
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> >
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