The Observer (UK News) has a good article by Antony Barnett, about just what goes on when one tries out a home genealogy/DNA kit. The Observer had four people use the tests, and the results were a little surprising. They point out the shortfalls of the tests as well.
Excerpt from the article:
As the genealogical craze continues to grow, private DNA tests are being launched in Britain to cash in on a seemingly insatiable desire to search for our ancestors.
Traditional genealogical methods can require months hunched over dusty documents and incomplete family records which may go back three or four generations. The firms marketing the new DNA tests claim the genetic code in a small amount of saliva can reveal traces of African, Asian, Middle Eastern or Chinese blood that might have entered a person’s DNA thousands of years ago as tribal groups roamed across the world.
On the one hand, they told people “one of your grandparents or great-grandparents were probably of this ethnicity”, but on the other, they had a margin of error of around 8%, which could be substantial after several generations. The whole process is very interesting, and DNA testing and genealogy has its uses – it can confirm branches of a family, etc., but going back further than a few thousand years….