J. James
You want sources, huh? Though many exist, I believe that the best evidence is that racists such as yourself have been trying for centuries to prove that such distinctions exist, but have failed at every turn- just look at how the scientific community shredded The Bell Curve, to cite a recent example. Here's a hint: all those people looking for something so hard, for so long? More likely than not, whatever they're looking for doesn't exist.
And you really need to brush up on your history. Selective breeding of slaves- while being massively played-up and exaggerated- was actually quite rare, and really only done in the American south during a short period. Far, far too little time for any major physiological changes or preferred mutations to occur, such as the differences you see between a bulldog and a Pomeranian.
And besides that, are you some kind of idiot? The slaves kept in "ancient times," as you put it, are not the same as the slaves kept by the South and Confederacy. Not the same groups of people, not even remotely. So even IF- and there is extremely little, if any, evidence that it occurred- selective breeding was done to, say, Jewish or Native American or European or Middle Eastern slaves, that has no bearing on the unrelated, free West African peoples that would eventually become slaves in the New World.
... Oh, and before you bring up "bias in the scientific community," I'd like to point out that scientists have historically taken the side of the truth, regardless of the condemnation or even death sentences they face for that. Besides which, the true "bias" would be to reject the conclusions of the scientific community as bias whenever they say something you don't like. And besides, many people want racism to be justified! As recently as the sixties, racism was the popular thing! But still, scientists cannot find any major differences between the races. Oh, sure, some melanin here, some slightly different rates of hereditary diseases there, various vague propensities and whatnot. All barely statistically noticeable, all dealing with averages and abstracts. Nothing, absolutely nothing, that would justify classifying nebulous "races" as subspecies, or treating people differently based on race. The differences are that minor, if they even truly exist at all.