This is an example of the type of question I receive all the time:
Here is some genetic analysis of Somalis from yours truly. I don't necessarily blame the public here, as the marketing of Y and mtDNA lineages has really gotten out of control recently. The problem is that the fine print that Y and mtDNA follow only one direct line of descent is usually there. But, it is accompanied by rich visual and narrative media that tells a story about that marker, and it is this that is salient for most. Not that the story being told is only a very small part of the overall epic cycle that is your genealogy. (Also, in population genetics using the word "Caucasian" is really confusing. G2 can often be thought of as a Caucasian haplogroup, but I don't think that that's what my correspondent meant)
