BBC News - Some DNA ancestry services akin to 'genetic astrology':
Scientists have described some services provided by companies tracing ancestry using DNA as akin to astrology. Some test findings tell people that they have links to groups such as Vikings, to particular migrations of people and sometimes to famous figures such as Napoleon or Cleopatra But researchers working with a campaign group say DNA tests cannot provide accurate information about ancestry.The article is interesting, but seems to skirt around the point that most concerns me.
I'm not likely to take a DNA test, mainly because of the expense, and doubts about their accuracy. Not, in the sense that the article suggests, of claiming that you are related to Napoleon, but how does one know that the samples that are sent to them are not contaminated, or mixed up with other samples, or even tested for DNA at all?
There's nothing to stop someone who wants to make a quick buck from advertising a mail-order DNA testing service, tossing any sample sent in the bin, and sending out prefabricated reports, just as there is nothing to stop mail-order astrologers from doing the same thing. And that is the thing that most concerns me. It is not the reports they concoct on the testing, but the method and accuracy of the testing itself that bothers me.
Assuming that the DNS testing is accurate, then, if it were also affordable, I might be interested. I belive it can show whether you are or are not likely to be related to a particular person whose DNA has been accurately tested. Thus if a a cousin and I are supposed to be descended from the same ancestor in the unbroken male or female line, a DNA test could show if it was so or not. I'm not sure that it it could show that as clearly in the case of mixed sex descent -- if my cousin is descended from my great great grandfather's sister, or great great grandmother's brother, for example.