Here is a short and incomplete list: ability to handle sun or lack thereof, ability to handle heat or lack thereof, ability to live in high altitudes, ability to process lactose, ability to tolerate alcohol, resistance to malaria, height.

There are also diseases correlated with groups of genetically related people.

However, these groups most often don't fit so cleanly into the US's constructs of race.

There could be mental skills correlated with groups of people with shared genetics.

The question is how we handle that if that is the case. One approach is to deny it. Another is to force or encourage people to have children with others to smudge out differences. Another is to let it be.

I suspect that the unspoken answer is denial while encouraging the smudging out of visible differences. I suspect that people are morally against the last and that it would lead to massive conflict.

I think a similar calculus has happened many times before. I think that is partially the origin of "whiteness".