[BroJoeK]

It's super-important to keep all this talk of DNA diversity in perspective.
Biologically speaking, the “human race” is not just one species, we are a single sub-species, with most of the differences amongst us being no greater than you'd find between typical dog breeds.

Yes, genetically, no two humans are identical and children are born with 60 new mutations, on average, from their parents.
But that's 60 out of THREE BILLION DNA base pairs, and most of those have no effect whatever on us.
So, the total of human DNA diversity amounts to one tenth of one percent of DNA base pairs.
This compares with around two tenths of one percent with Neanderthals and around five percent with Chimpanzees.

Point us that genetic differences amongst humans are relatively small, and even though evolution (or de-evolution if you prefer) continues every day, we are still much more alike than different from each other.

[Zhang Fei]

Point us that genetic differences amongst humans are relatively small, and even though evolution (or de-evolution if you prefer) continues every day, we are still much more alike than different from each other.

That goes without saying. That's why interracial procreation can occur without systematically producing sterile offspring. On the other hand, the tiny differences are sufficient to account for great differences in mental and physical ability, just as they are in other species. And to put things in perspective, pigs and humans are said to have 98% of their genes in common.

[Zhang Fei]

The reason these small differences need to be researched thoroughly is that it would be nice to find a way to tweak the genes that affect intelligence, susceptibility to sickle cell anemia (prevalent among blacks), diabetes (prevalent among Asians and Pacific Islanders) and so on.