Sherlock Holmes wrote: > T.M. Sommers wrote: >> singhals wrote: >>> cecilia wrote: >>>> Huntersglenn wrote: >>>> >>>>> [...].the likelihood of the government or an insurance company >>>>> knowing about the DNA genealogy testing isn't all that great. IF >>>>> either entity wanted my DNA that badly, they'd most likely opt to >>>>> get it directly from me, or from my house, or my doctor. [...] >>>> >>>> An insurance company might be as interested in the ages at and causes >>>> of death of one's last three generations of ancestors. >>> >>> Another reason not to put too much on line? (g) >> >> The markers used in these sorts of tests are in the junk DNA. Since >> they don't code for genes, there is no selection pressure on them, so >> they make better molecular clocks. If they did code for genes, then >> some mutations would be lost because they were fatal. But with junk >> DNA all the mutations stick around, because they don't matter, so you >> can, with an assumed mutation rate, measure when two lines diverged. > > So in actual fact DNA Genealogy is guess work at the best Not at all. 'Assumed' in this context simply means that the value is, as far as the present calculation goes, a parameter. It does not mean that the value has been arrived at by guesswork, only that it has been arrived at elsewhere. And don't assume that you know what 'parameter' means; it has a specific technical meaning in mathematics. > and thus can > not be relied on concerning the number of generations involved due to > the AssUMed mutation rate. The mutation rate is much too low to be used as a clock in genealogy. The whole point of the exercise is that you can build trees because the rate is so low that many generations will pass by with the DNA unchanged. The reason mtDNA and Y DNA is used is that those two pieces, and only those pieces, do not undergo recombination, and are passed intact from parent to child. -- Thomas M. Sommers -- tms@nj.net -- AB2SB