John, J.S. Plant wrote: >Hi Jim, > >Mostly I am busy at the moment and staying well out of this. I >couldn't resist a brief remark on the following however... > Somehow, I'm not too surprised--given our past discussions on the limitations of genealogical DNA research. >Reliability isn't really a problem. One can always get the test done >with another testing Laboratory and see if the results are the same. >In fact that is what we are currently doing with the >Plant(agenet)-like name project, though mainly with the objective of >measuring more markers to limit the generation-range of the MRCA. I >do not really expect the results to be different, as others have >cross checked many times before and they report that, with reliable >companies, discrepancies are essentially non-existent. It is always >good to be able to double-check important results however. One of the >main strengths of the scientific method is that people can always >repeat an experiment to check its validity (unlike the situation with >an old report by one person about events). > The mere fact you and others have cross-checked information indicates it is a potential problem. Why else would any of your group re-checked their data? My only thought is that if major criminal DNA labs are having these problems, why not other labs providing less critical genealogical DNA testing? Cross checking aside, who would know? >I am not claiming that the DNA method is the answer to everything. >Far from it. In my experience the main problems are the limited range >of the situations for which DNA can give an answer, the expense of >the test (even if one doesn't repeat it), and the difficulty finding >volunteers to take the test. I do not think that the reliability of >the test is an issue however. Far from it. > We seem to agree the DNA test are not a genealogical solution, but rather an aid. And again, the reliability is always a question or none of your group would have retested. In your particular application the tests have a greater importance simply because yours is more one of a one-name study rather than a genealogical tree. So the fact this affects a fraction of 1% of one's overall tree and the probability factors involved with the MRCA work better in your situation. The comment was originally in a genealogical context however. Jim

Jim, > We seem to agree the DNA test are not a genealogical solution, but > rather an aid. And again, the reliability is always a question or none > of your group would have retested. In your particular application the > tests have a greater importance simply because yours is more one of a > one-name study rather than a genealogical tree. So the fact this affects > a fraction of 1% of one's overall tree and the probability factors > involved with the MRCA work better in your situation. The comment was > originally in a genealogical context however. I agree that your comments were originally in a more general genealogical context and that confusions can arise unless the differences between the objectives of different projects are pointed out. For those interested I shall try to explain some of the differences in objectives a bit further. For those who are not interested in DNA testing, read no further. We do indeed seem to agree that DNA testing at random, without any clear objective in mind, is unlikely to be informative but that there are occasions where it can be a useful aid. We seem to agree furthermore that Y-line DNA testing is most conveniently and most usefully carried within the context of a one-name society. Many who thought that they were related, because they shared the same surname, are finding from DNA testing that they are not related at all. The Plant name bucks this general trend - it was generally said that they were an assortment of unrelated gardeners whereas in fact the DNA shows that the Plants are largely a single family. Another example is the Mumma surname study which showed that those with the USA name spelling Mumma matched with the spelling Momma in Estonia but not with Mumma in Germany. This is the sort of information that Y-line testing is good for. In the Plant(agenet)-like name study so far, most of those with the spelling Plant have matched with one another and one of the Plant volunteers tells me (and I have no reason to doubt him) that he descends from the spelling Plantt. Certainly there is widespread evidence in records for the spelling Plantt. However two with the spelling Plante have not matched and we have not had any volunteers so far with the Swiss noble name Planta nor with the French name Plantard which has been claimed to have fathered *Planta* in *England* (not there is evidence of Planta as opposed to Plant in England). Nor do I yet know of any Y-line measurements for an acredited male-line descendant of the Plantagenets though the Warrens are actively testing with that objective in mind. Without boring list members with too many technical details, our objective for repeating some of the Plant tests is not primarily to check the results though it is always a bonus to be able to do so. It is more that the Plant results matched together so well that we cannot tell by our DNA results alone one Plant branch from another. The initial tests with Oxford Ancestors measured 10 markers for each volunteer and we are sending some of these to FT-DNA so that we can measure 25 markers for each volunteer. By measuring more markers we increase the chances of finding small Y-STR mutations between different branches of the Plant family, since a few such mutations can be expected to have arisen of the time span of a surname. In the longer term this is also helpful in tying down the MRCA of the family as a whole. Of the 25 newly measured markers for each volunteer 9 will be the same as those previously measured and this provides a means of checking the reliability of the test results though this was not the *primary* objective of the "repeat" measurements as I have explained. I guess not everyone on this list is interested in all of these details but hopefully this will help sweep away some of the misunderstandings that so far tend to surround the new techniques of DNA testing. I note that you are not alone in not getting a warm fuzzy feeling from hearing about the DNA techniques but, as time passes and the benefits and shortcomings become more widely known, I guess that tiny little outbreaks of warmth and fuzz might gradually begin to appear. Best wishes, John -- . . John S Plant PhD MBCS MIDI KLUO . Chartered Information Systems Practitioner .......unifying cerebral creativity with intelligent algorithms Tel.(01782)58 3064 : j.s.plant@isc.keele.ac.uk :: Computing Services, Fax.(01782)58 3636 : helpdesk@isc.keele.ac.uk ::: Keele Information Services. .....Dr.J.S.Plant,Computing Services,Keele University,Staffordshire,ST5 5BG.