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 > > > > > > > > > > > > > > > > ==== ARIZARD Mailing List ==== > > For an index to most user mailing lists hosted by RootsWeb, visit > > http://www.rootsweb.com/~maillist/us/index.html > > > >To subscribe, change options, or unsubscribe please see the instructions at >http://listlva.lib.va.us/archives/va-roots.html To subscribe, change options, or unsubscribe please see the instructions at http://listlva.lib.va.us/archives/va-roots.html