[fdsaaf]

Why would it be surprising that the child of someone who is white and someone who is half white might go on to appear mostly white? You yourself mention that your genetic makeup (presumably from 23andme or something) also suggests a "mostly white" appearance. In this case, there's a pretty good match between phenotype and genotype.

You absolutely can predict someone's phenotype from her genotype, roughly speaking. In cases of recent admixture, the exact gene expression can be uncertain. Just look at Mendel and his peas! Even this variable heredity has limits. There was a zero percent chance that you'd end up looking like a typical Japanese person.

I don't understand your point. I'm not claiming that the classic races are fixed for all time. I'm not suggesting that we can't arrange genes in new combinations. I am claiming that people today cluster in certain historically-contingent ways and that these clusters reflect the everyday understanding of race.

[grardb]

It seems like you don't understand my point because you've ignored the fact that my mother and her sister look they belong to different races, despite having roughly the same genetic makeup (about half white and half non-white). My result is not surprising; theirs are, however.

As another commenter said, what about Obama? I've met people who are half black and half white and end up looking like white people. Obama doesn't look like someone from Africa, nor does he look like someone from Europe. Because of what society determines as being white, most people would say, "he looks more black," which isn't really true, but regardless, you likely would not be able to tell just by looking at his genetic makeup. Many people in the same circumstance look wildly different from him.

If your argument is that when someone's genes all come from one area, then you can take a guess at what they might look like, then sure. But to apply that blanket statement to the entire world is just not the case. There are parts of the world where those lines get very blurred (e.g. Turkey, Nepal, Afghanistan), and plenty of people who are of "mixed descent" with different phenotypes from you would predict from their genes.

[ptaipale]

I don't see it as very surprising that your mother and her sister look like they belong to different races. That's how genetics works in case of individuals; siblings can get different sets of dominant and recessive alleles from their parents.

In terms of population, things then average out. There are indeed parts of the world where things are very blurred because of extensive human interaction across populations. If every place in word were like that, then there indeed wouldn't be what we call races. But most of the world is not quite like that, and particularly, in the course of history it hasn't been.