Where did we come from?

On a recommendation from my father, I had a look at Oxford Ancestors, a for-profit genealogical DNA testing company. Interestingly, they offer maternal and paternal DNA testing services to identify to which "clan" you belong. Bryan Sykes claims that there are seven maternal clans, corresponding to the so-called Seven Daughters of Eve. Other human genealogists claim there are, in fact, 10-12 clans, including haplogroups I, M and W. All very interesting. Above is an image from Wikipedia describing the migration of the human race out of Africa, according to mitochondrial population genetics.