Dutch and German people only differ a little bit, because they belonged to the same people until relatively recently. Germanic and Romanic people differ more, because they got seperated thousands of years ago. And blacks and whites differ even more, because they've been seperated for a long time.
We can say that chimpanzees and humans are different species, because scientists made rules to divide animals into groups: two animals belong to different species if they can't get a fertile offspring. However, since animals are constantly evolving, actual different 'races' or 'species' or 'families' don't exist. They're a human attempt to create order in the plethora of different animals. So of course, the difference isn't alwasys clear. With lions and tigers for instance, it's hard to say whether they're seperate species or not.
TL;DR: living species are dynamic and any form of division is nothing but a human construction.
Deny it all you want, but DNA isn't a "human construction"...
Oh good. So we have some rules in place for this, now?
So tell me, what is the % of change between two samples of DNA that we're able to classify them as belonging to a different race? Obviously the rule would have to correctly classify the correlation between every combination of race x to race y, in order to be scientifically recognised, correct?