Darwin loosely used the term races to refer to animals with common ancestors which had become separate species. Now, for example, horses and donkeys have a common ancestor, and they can breed--but their offspring are sterile, so they are separate species, or, in Darwin's term, separate races. The term race as applied to humans derives in the late 19th or early 20th century, and it's completely specious. (I believe the term racist only dates to the 1930s.)
In modern biology, separate species can be defined by the inability to produce offspring which are not sterile, or sexual isolation. So, for example, polar bears and brown bears (like grizzlys) have a recent common ancestor, and it appears that two of them recently mated and produced an offspring. Some son-of-a-bitch shot the boy, so we don't know if he was sterile or not. But the other criterion, even if two members of separate species could mate and produce reproductively viable offspring is sexual isolation. The holy rollers got all worked up over the polar bear-grizzly mix, trying to claim that it "disproved" evolution. But polar bears and brown bears are separate species because of sexual isolation. They don't go to the same pubs, so they don't hook up.
Now, i'm sure you're wondering what any of this has to do with this sick racist's ranting. Humans are obviously not divided into separate species because they can mate and produce reproductively viable offspring. But the more we learn about culture, language, achaeology and genetics, the more information we possess to show that sexual isolation does not apply to humans, either.
The major linguist, cultural and ethnic group in south Asia thousands and thousands of years ago were the Australasians. We might think of them as Chinese (although that would be anachronism). Well, Australasians crossed to Formosa (Taiwan), and from there to what we call the Philippine Islands. Then they colonized the Celebese, Borneo and what we think of as Indonesia. Eventually, their descendants spread out to the east and are now the Polynesians. But they spread out to the west, too. Madagascar was colonized by Australasians, probably from Java or Sumatra. The ancient cultural and linguistic evidence surprised European researchers with the evidence generations ago, and has since been confirmed genetically. I believe (i'd have to look it up) that Madagascarians (?) are about 40% the genetic descendants of Asutralasians, and the archaeological evidence is that they got to the island before African tribesmen did.
There is a tribe in southern Africa called the Lemba who claim to be descended from the lost tribes of Israel. Well, guess what? A Harvard geneticist (who happens to be a Jew), checked them out, and found that about half of Lemba men have Y-chromosomes of Jewish origin. More significantly, the Buba clan supply their priests, and they have the the Cohen modal haplotype, which means they are descended from the Kohanim, the ancient Jewish priestly caste.
There is an hypothesis called the Solutrean hypothesis which is based almost entirely upon methods of producing flint tools. In western Europe in the period of roughly 35,000 to 25,000 years ago, there was a dominant culture we call the Solutreans. They produced flint tools by a method known as pressure flake knapping, which can produce extremely thin and extremely sharp blades, such as knife blades and spear heads. A little thought will tell you that an extremely thin, extremely sharp spear head will be much more effective for piercing the hide of a prey animal with a heavy coat--this is a valuable skill. Well, the Magalenan culture which succeeded the Solutreans did not do pressure flake flint knapping--in effect they were using an earlier, clumsier method.
The only other occurance of pressure flake knapping showing this high degree of skill at any time more than 10,000 years ago are the Clovis points (named for the site of the first find near Clovis, New Mexico) of the early Amerindians. Now personally, i don't believe in inventive isolation--it's possible that an idea can occur in several places at several times. But pressure flake knapping is an example so unique--found only among the Solutreans and the Clovis culture tribes--as to suggest that this was a subtle innovation which just didn't occur to very many flint knappers at all.
So, the Solutrean hypothesis has it that people of the Solutrean culture made it to North America about 20,000 or 25,000 years ago (which would make them the original tenants), and that Clovis flint knapping technology derives from that. It's a fringe hypothesis, not accepted by most scholars in the field. However, some disturbing discoveries cut into their arguments that Clovis culture independently devised the method. Clovis points have a distinctive diagonal pattern in the pressure flaking not seen in the Solutrean points, which was considered a strong argument against the Solutrean hyposthesis. However, in recent years, pressure flake points have been turned up in the eastern United States, and they don't have the distinctive diagonal pattern of Clovis poinst, and they're older
than the Clovis find. The people who have dug up them have been ostracized--academics who have a career stake in a certain world view don't appreciate being contradicted.
But more telling is the work of a Canadian geneticist who has shown that in both North and South Ameicans, on average, 3% of Amerindians have ancient European MtDNA (the DNA of the mitochondria)--ancient as in they didn't get it from European after 1492, its MtDNA from tens of thousands of years ago. A more damatic piece of the puzzle, though, is that the incidence of ancient European MtDNA in Amerindians in eastern Canada rises to 25%. That cuts into the dismissal of academics who say it came through Siberia (even though modern Siberian tribesmen don't have it).
Now, of course, this doesn't prove the Solutrean hypothesis, but it sure does upset a lot of academic apple carts.
So, humans are not separate species by the test of reproductive viability, and recent genetic evidence dismisses any claims anyone would care to make about sexual isolation
. Simply put, there is one, and only one, human race.