Human DNA ethnicity tests

Yesterday I was talking to a friend about how I won't know about a lot of my baby's technical heritage - his/her father is adopted, of hispanic and/or mixed (black, native) descent, and I know little about my biological father's heritage (except the supposed makeup doesn't really add up), and my maternal's family has been here since the early 1600s, so all I know is French and some mix of other Western/Northern European cultures.

My friend said that because her father's family frequently lies or "changes" what they consider their ethnicity (fairly understandable considering the racism I know some of them have faced, even here and now), her mother ordered her a DNA test to tell your genetic makeup. Presumably similar, and about as reliable, as those dog breed tests.

However, supposedly the test can't tell your exact heritage or genetic makeup, just generalized ethnic groups and the areas from which those genetic makeups are most commonly found. So if you're African, it can tell you a general area of Africa where your genetic makeup was believed to originate, or it determines European by Mediterranean, Middle Eastern, Northern Europe, etc.

Has anyone done this? Or does anyone who knows anything about genetics (Hey Dekka!) know about these? I'm not sure exactly what information it can tell you, but it might be fun. Not sure if it's $50 worth of fun...I guess I'll wait til my friend takes hers and see what it comes up with.

I would do it on myself just for fun!

Ok, if you're talking about what I think you're talking about, there are tests that look at mtDNA haplogroups, which I know a little bit about since my mom does these tests with some of her genetics classes. Basically, humans went through a genetic bottleneck about 60,000 years ago in Africa, and only one mitochondrial DNA type (passed through the maternal line) survived. Then as populations spread through Europe, Asia, the Americas, etc. they acquired mutations in their mtDNA. So people who settled in different areas will have a different set of mtDNA mutations, and these sets are called haplogroups. A geneticist can analyze your mtDNA to see what haplogroup you belong to, and see what general area your ancestors were from.

As far as I know these tests are pretty accurate, though not very specific in that they can't tell you where your grandparents, great-grandparents, etc. came from - it's more looking on the time scale of thousands or tens of thousands of years. It's really cool information to have, since you can trace your ancestors' migration routes out of Africa, and find out where most of your ancestors are from. I've never done it myself but I've heard the results can be surprising.

I've also heard of other tests related to Y-chromosome haplotypes that can give you more recent information (useful for tracking last names in genealogy) but I don't know very much about it. I'm guessing an ethnicity test like you're describing might be a combination of some of these tests.