How accurate are DNA tests?

[suzy_q2010]

Originally Posted by MissesAnna

I recently ordered a Dnatribes.com test and I am just wondering what the accuracy really is for these tests. I ordered it for my grandmother (15 marker test) and I am also curious how much better a 21 marker test really is than a 15 marker test.

Is anyone knowledgeable of these DNA kits?


Thanks for your input!

The tests are accurate. Your DNA will have the markers that are being tested for, and quality control is of neccessity stringent. Could your sample get mixed up with that of another person? Yes, but it is unlikely.

I think that your real question is whether doing more markers is more useful in identifying potential true relatives. The answer is yes, because you will get more matches, if you do fewer markers, with people with whom you share ancestors so distant that finding the paper trail that tells you who the shared ancestor actually was is very difficult.

The usefulness of the test also depends on how many of your relatives are being tested. If few of your ancestors' descendants are interested enough in genealogy to get tested, you will not get many matches.

So far, I have had two relatives get YDNA tested. My cousin did it for one of my mother's family's lines. We have two 37 marker perfect matches, neither of whom has the same surname as my cousin. We have many, many 25 marker matches.

My brother did it for our father's line. We have three 37 marker matches with his surname. All link to Virginia, but we cannot connect all the families to an actual person.

The advantage of autosomal testing is that it finds matches for lines other than the direct paternal one. That means women can be tested, too. But you still have to do the paper hunt to find how you are related to a specific person.