> >Glenora: > >Could you give us some idea of what you mean by "the relatively low rate >of success."? I'm curious as to what was being sought that, not being >found, lead to that conclusion. > >Y DNA is not a substitute for paternity tests, and it can't tell you the >exact relationship between two people who have a perfect match on their Y >DNA signature. It can tell you if you are or are not related to someone >of the same surname, and it can tell you the ethnic background of your >direct male line ancestor. > >So, we can use it to see if any of the Northern and Southern Davenport >fanilies are related and, assuming we can determine his Y DNA signature, >we can determine if Davis Davenport was of male Native American or >African or Caucasian ancestry. > >Regards, > >Steven C. Perkins Steve, Nothing was being sought, nor did I say so. I am not an expert, but I do know that if 2 people have a total match of all 12 markers, they are *most likely* related. But, there is still only a 50% chance that their common ancestor lived within the last 14 or so generations, or about 600 years. If even one marker is off, there has been a mutation since that common ancestor was alive which makes a more distant relationship likely. Two markers being different is slipping into questionable results, and three is deemed not related. There can be and often are mixed relationships, bastard children as an example. Thus, another way that lines can be less than clear. At some point, basically from those still living (or access to DNA of the departed) back, it is still a matter of trusting good genealogy and research. No, they are not taken as paternity tests, but can be used as such, or in other ways. Once you part with your DNA one must be quite trusting of the possibilities. Is it destroyed? Is the data? Who holds it and what is the security? Is learning the ethnicity of a patriarch of enough value to become part of a data base and pay the costs involved? I'm not saying these are problems with any particular company, but personally, they are things I would look into quite thoroughly before deciding. My friend who had this done was also asked to fill out family charts, which she did. An error in their transcribing ruined the whole process anyway, so the results were of no value to her, or anyone. But they did muddy her genealogy waters so to speak. I admit a sensitivity to this subject, which also causes me to fully support most genetic research. We have a genetic disorder in the family that has left one of my daughters disabled, and has mutated to another form of the disorder in a grand-daughter, just one generation. Of course that is quite a different topic, but the time I've spent with geneticists has been educational. I do believe that in a few years the testing for family lines will be much more refined, and the ethics as well. So again, all I did was suggest people investigate before committing their money and information. And for those wondering, the disorder is not from the Davenport side. Glenora

Glenora: Thanks for your reply. I can understand your concerns. From a study done by the members of the Genealogy-DNA-L list at Rootsweb, we have found that, in the tests where the results are publicly available, 30% of the 12 marker matches fail at 25 markers. Fail is defined as 3 or more differences in the markers. This means the 25 marker test is usually required to validate a 12 marker match. WIth a 25 marker test, the time to the 50% level for the MRCA is 7 generations. A 35 marker test could cut the 50% level to 3 generations. Both are well within the time frame when we can hope to find supporting documentation. Most of the more recently started Y DNA studies tend to encourage the 25 marker test, instead of the 12 and upgrade. The US government has proposed a 65 marker test, and we are waiting to get the technical details. The Genealogy-DNA-L list is gathering evidences of the mutation rates between related testers to try to determine the mutation rates at various markers. We believe this is one instance where amateurs can make a contribution to the scientific literature, since most scientific studies are of non-genealogically linked populations. As to the ethics, I trust the company I went with and their scientific laboratory not to share my DNA sample with anyone else. Can I be sure of that, no, do I worry about it, not very much. The US govenrment already has my DNA and they will do whatever they want to with it. Illegitamacy and adoptions are part of life. I recommend that no one have the Y DNA testing, unless they are sure they will match the rest of their family, or unless they are looking for a difference. While the degree of relationship can not be determined, a non-match is easy to see. Errors in documentation, clerical errors in transcription, etc. are always with us. We simply have to be careful in our research and documentation. Again, this is a tool to be used in our research, it complements our record research. Like you, I have no doubts that it will be improved in the future. Take Care, Steven C. Perkins On 22 Jan 2003 at 0:06, Glenora Chamberlin wrote: Date forwarded: Wed, 22 Jan 2003 01:06:23 -0700 Date sent: Wed, 22 Jan 2003 00:06:26 -0800 Forwarded by: [email protected] From: Glenora Chamberlin <[email protected]> Subject: [DAVENPORT] Re: DAVENPORT-D Digest V03 #27 To: [email protected] Send reply to: [email protected] > >Glenora: > >Could you give us some idea of what you mean by "the relatively low rate >of success."? I'm curious as to what was being sought that, not being >found, lead to that conclusion. > >Y DNA is not a substitute for paternity tests, and it can't tell you the >exact relationship between two people who have a perfect match on their Y >DNA signature. It can tell you if you are or are not related to someone >of the same surname, and it can tell you the ethnic background of your >direct male line ancestor. > >So, we can use it to see if any of the Northern and Southern Davenport >fanilies are related and, assuming we can determine his Y DNA signature, >we can determine if Davis Davenport was of male Native American or >African or Caucasian ancestry. > >Regards, > >Steven C. Perkins Steve, Nothing was being sought, nor did I say so. I am not an expert, but I do know that if 2 people have a total match of all 12 markers, they are *most likely* related. But, there is still only a 50% chance that their common ancestor lived within the last 14 or so generations, or about 600 years. If even one marker is off, there has been a mutation since that common ancestor was alive which makes a more distant relationship likely. Two markers being different is slipping into questionable results, and three is deemed not related. There can be and often are mixed relationships, bastard children as an example. Thus, another way that lines can be less than clear. At some point, basically from those still living (or access to DNA of the departed) back, it is still a matter of trusting good genealogy and research. No, they are not taken as paternity tests, but can be used as such, or in other ways. Once you part with your DNA one must be quite trusting of the possibilities. Is it destroyed? Is the data? Who holds it and what is the security? Is learning the ethnicity of a patriarch of enough value to become part of a data base and pay the costs involved? I'm not saying these are problems with any particular company, but personally, they are things I would look into quite thoroughly before deciding. My friend who had this done was also asked to fill out family charts, which she did. An error in their transcribing ruined the whole process anyway, so the results were of no value to her, or anyone. But they did muddy her genealogy waters so to speak. I admit a sensitivity to this subject, which also causes me to fully support most genetic research. We have a genetic disorder in the family that has left one of my daughters disabled, and has mutated to another form of the disorder in a grand-daughter, just one generation. Of course that is quite a different topic, but the time I've spent with geneticists has been educational. I do believe that in a few years the testing for family lines will be much more refined, and the ethics as well. So again, all I did was suggest people investigate before committing their money and information. And for those wondering, the disorder is not from the Davenport side. Glenora ==== DAVENPORT Mailing List ==== For instructions on unsubscribing or searching the list archives visit: http://homepages.rootsweb.com/~nvjack/davnport/group.htm ============================== To join Ancestry.com and access our 1.2 billion online genealogy records, go to: http://www.ancestry.com/rd/redir.asp?targetid=571&sourceid=1237