Frequently asked questions

Frequently asked questions

<p><strong>Q: Is there more than one kind of DNA test for genealogy purposes?</strong></p> <p>A: Yes - for males, Y-chromosome DNA tests examine markers on the Y-chromosome which are handed down virtually intact from father to son across many generations, because a mother has no Y-chromosomes to mix with the father's. For females, mitochondrial DNA (mtDNA) is inherited in a manner similar to Y-DNA in males. However, mtDNA is not associated with particular surnames. Only males can supply a sample for Y-DNA investigation of paternal ancestry, but males or females can supply a sample for mtDNA investigation of maternal ancestry.</p> <p><strong>Q: What kind of test should be used for a one-name study?</strong></p> <p>A: In a society where surnames are inherited from the father, the Y-DNA test is the one to use for general lineage purposes.</p> <p><strong>Q: What do I say to a correspondent whose grandmother (or other female ancestor) was born with "my" surname, who wants to explore their roots in that surname using my study's DNA project?</strong></p> <p>A: Your correspondent's grandmother (or whoever) probably had brothers or uncles who had "your" name. He/she should find one of those brothers/uncles (or a male-line descendant thereof) and persuade him to join your project. <br /> <br /> <strong>Q: Can an ancestor's hair be tested?</strong></p> <p>A: Maybe, but it's not easy. A lock of hair cut off with scissors doesn't include any hair roots and therefore has no nuclear DNA (in particular, no Y-DNA), only mtDNA. A complete hair found in a comb or brush might work if it has been kept in a cool, dry place. A tooth might also work, though old shed deciduous teeth (commonly called milk or baby teeth) may not retain the dentine required for a DNA analysis. Even an envelope or stamp that was licked by a known ancestor might have traces of DNA. However, extraction from such sources is a very specialized job, and most testing laboratories don't do that sort of thing. One case that has been examined is hair reputed to come from Sir Isaac Newton, which proved to come from several different people. You can read <a href="http://abc.zoo.ox.ac.uk/Papers/currbiol04_hair.pdf" target="_blank">a technical paper on this subject</a> (pdf format).<br /> <br /> <strong>Q: What about exhumation?</strong></p> <p>A: Theoretically possible, though permission to exhume may be difficult to obtain, the DNA tends to break down very quickly if the body has been embalmed and then buried in soil, there may be difficulty identifying the correct grave, and again most testing laboratories do not do that type of test. <br /> <br /> <strong>Q: Does it hurt?</strong></p> <p>A: No. The test does not require blood, only a sample of loose cells collected from inside the mouth using a pair of swabs. A kit is mailed to the person being tested, he does the swab himself, and the sample is sent to the laboratory by mail.<br /> <br /> <strong>Q: Is this anything like paternity testing?</strong></p> <p>A: They both use DNA but are otherwise very different. For one thing, paternity tests must work for both males and females, but your project's Y DNA testing will work only for males. Also, Y-DNA testing cannot pick out a person's father from among a collection of his same-surname male relatives.</p> <p><strong>Q: Is this anything like the tests used for identifying criminals?</strong></p> <p>A: No, those are generally the same as paternity tests.</p> <p><strong>Q: Is this anything like the screening tests used by insurance companies?</strong></p> <p>A: No. The markers tested for genealogy do not detect diseases. <br /> <br /> <strong>Q: What can people learn from this testing?</strong></p> <p>A: In simple terms, it will determine (very approximately) how closely a person is related to other people who take the test.</p> <p><strong>Q: Doesn't this testing reveal mutations? Aren't mutations bad?</strong></p> <p>A: The markers examined have no genetic function, and therefore mutations in them are harmless. In fact, they are essential for genealogical purposes, since they distinguish one family from another.</p>