Thursday, June 9, 2011

You can find ancestors through DNA testing?

DNA testing for family history research--go for it! 
It used to be the case that men could have some fun tracing their y-dna lines back to a progenitor who would be their father’s father’s father’s father’s father and on and on. The line goes back pretty far in time, and at some point the mutation that became their line appears. With diligent work, it might even be possible to see where that line connects with related paternal lines. Sometimes the surname will be the same all the way back, and sometimes there are interesting, and often unexplained changes. Someone testing as “Jones” might match best to men with the surname “Dexter.” The change could point to an adoption, or to a “non-paternal event.”  
Then along came mtdna, and women could trace the mother of their mother, and so on back in time. Sometimes there will be a perfect match in the mtdna with another person testing, and the match may reveal something about the common ancestry. At the very least it will indicate some common names or geography.
Those tests are interesting, and fun to work with, but much more interactive fun can be had in family history research with testing autosomal DNA. When you test your autosomal DNA, you are provided with matches whose ancestry will match yours in some way within about ten generations. The level of matching is usually predicted, and is generally accurate. If the testing company predicts that a match is your fourth cousin, it is likely that they are a fourth to a sixth cousin. Because the results tend not to show anything beyond ten generations, it is not necessary to look way back into the 1600’s to find the common ancestor. That said, finding the common ancestor can be pretty tricky! Matches correspond and try to narrow down the possibilities. Looking at common segments in the chromosomes can be helpful too.  DNA testing won’t pick up all the possible matches since it only tests parts of chromosomes, and since what each person inherits from the previous generation is only part of that previous generation’s genetic make-up.
New matches are added to the database constantly, so the opportunity to correspond and to develop more information about the potential ancestors you may share increases.
But it doesn’t end there. There are more fun things to do with the results, all very interesting and addictive, and so far, at no cost.
Some of the great sites to play around with matches and the matches of matches, and DNA segment comparison are and HIRsearch. Both sites are easy to navigate.
To check out what research has been done on your specific traits, you can run results through Promethease. The research on human DNA is relatively new, so results at Promethease are updated often. You can see whether you might have increased risks for certain conditions, or reduced risks, and you can check interesting little traits like detecting bitter tastes, eye color, curliness of hair, and so on. The results are based on studies to date, and do not ever define your genetics definitively. The results are just interesting to see and think about.

No comments: