On Saturday, June 11, 2016 at 12:11:49 PM UTC-7, taf wrote: > On Saturday, June 11, 2016 at 8:53:34 AM UTC-7, Vance Mead wrote: > > I have some questions regarding the use of DNA in genealogy, in view of > > the recent postings on the subject. > > > As far as I can tell - and I am certainly no expert - DNA testing can > > supplement documentary evidence in a few ways: > > > > - It was used to prove that the skeleton found in Leicester was in fact > > that of Richard III. > > Just to be absolutely precise, it was used to show that the skeleton found at Leicester shared the same mitochondrial haplotype and documented descendants of the maternal lineage of king Richard III. It showed him to have a different haplotype from documented descendants of his paternal lineage. > > > - It could show if Granny had a secret she never told Grandpa about who > > was Dad's father. > > If Grandpa is still alive, or left behind a high-quality, uncontaminated sample that could be tested, then it could demonstrate this directly. Otherwise, it could do so implicitly, if descendants of Granny had a different Y-DNA haplotype than descendants of multiple brothers of Grandpa. If there were not multiple grand-uncles with descendants, then testing of the descendants of one, plus the descendants of more remote male-line kin would also demonstrate this. > > > - It could show if people with the same surname are really related. > > We are all related (see below). It could indicate that two people with the same surname derive from the same male lineage within a reasonably small number of generations, but could not define that number. > > Why I said we are all related: a very-distant cousin of mine had his DNA tested along with that of another person of the same surname. The company who performed the test reported back that 'Congratulations, you are indeed related'. When he showed me the report I read the small print (which being aged 94, he could not do), where they classified what they meant by 'related' - that they shared a common male-line ancestor within the previous 25,000 years. In other words, they were both white, but that's about it. This was about 15 years ago, and I don't think any company would try to pull this kind of thing now. > > > In my case, there were several Mead families in Oxon/Bucks/Herts in the > > 15th and 16th centuries. One question: how far back is this reliable? For > > example, there are proven descendants of Thomas Mede of Henley on Thames, > > Oxon, born about 1550, and of Richard Mede of Watford, Herts, born about > > 1515. They are probably unrelated, but could DNA show a theoretical > > connection between them some 15 to 20 generations ago? > > Yes, it could. > > > > - I have seen how it has been used to show that two people are fifth > > cousins, or whatever. Is this only in the male line, or in all possible > > relationships? > > Male-line testing or female line testing can only show that you are of the same male or female lineage, not the number of generations (unless you have very precise information that is beyond the scope of most testing). > > There is another type of testing, Autosomal testing or SNP testing, hat can tell if two people are distant cousins, in the range of 2nd - 6th or so, but it cannot tell you precisely how close. > > > I can see how DNA could be used to support documentary evidence, much as > > archeology is used to supplement historical evidence. Could someone give > > a brief summary of how it is used in genealogy? > > I can give several examples. If a man married two wives and you don't know which was mother of a female child, then you could test maternally-inherited mtDNA for a female-line descendant of that child, and also from descendants of sisters of the two wives, and whichever matches, that is the family to which the child's mother belongs. > > Another female-line example. If there were two first cousins, daughters of brothers, both with the same name and no document to determine which was the later wife of that name, then testing female-line descendants and comparing them to the lineages of the wives of the two brothers would tell you which couple's daughter was the one who married. > > Male line examples: Your name is George Webster, and you can trace your male line back through the censuses to 1800 in New England, but not before. You find records in town histories that identify multiple Websters there, some descended from Gov. John Webster of Conn., others descended from the other John Webster, ancestor of Congressman Daniel Webster. You can compare your DNA to descendants of both immigrants and determine whether your line descends from one or the other (or neither). Likewise, as you suggest, you can determine if two immigrants of the same surname were of common English origin. In a family blessed with a lot of tested samples and a lucky mutation or two, it could even narrow down to which branch of a family a line belongs. > > Male-line testing is also very useful in cases of illegitimacy or poorly documented paternity. I have a Rev. War ancestor who is first documented picking a guardian at age 14 as the son of an unmarried woman. He has a different surname than her, and based on this, I have a guess who the father might be. DNA could be used to confirm that my guy shared the same Y-chromosome as his prospective son. > > In terms of the Autosomal testing, the earliest uses are still the most rigorous. It can demonstrate unambiguously 'who's your daddy' as long as everyone is still around to be tested and your daddy didn't have a twin brother. More generic applications are 1) a fishing expedition for missing information - you will get a list of distant relatives, and by sorting out how they relate, it may reveal connections you don't know about. > > It can also be used more directly to confirm a pedigree. My Pennsylvania g-g-grandfather 'died due to a fall from a ladder'. It must have been a long ladder and took him a long time to croak, because he landed in Kentucky with a different wife, or so it seems. There are no male-line descendants on my side, and no absolute proof the two are the same man, so I could do an autosomal test with a Kentucky descendant and if it reported a connection in the 2nd-to-5th cousin range, then it would be a strong indication that I have things reconstructed correctly. If it also showed linkage to someone else not descended from either the Pa or Ky group (and the common ancestor is close enough that both are fully documented) then it may provide a clue to where he came from (and perhaps reveal that this was not the first ladder he fell from). > > Those are just some examples. > > taf I understand that DNA testing has shown that Samuel Pickering of Pennsylvania is not connected to the Pickerings of Salem, Massachusetts, and, making it more interesting, the Salem Pickerings are apparently not related to the Yorkshire Pickerings, although the Pennsylvania ones are, in some as-yet-unknown way. I also understand that Moses Knapp of West Virginia and his brother Joshua (both born in New York state) have been shown by DNA tests to be of the family of Nicholas Knap of Connecticut - but again, the connection is not yet known.