throwaway538

This is because phenotype is a good predictor of genotype and people are good at assessing someone's phenotype very quickly.

I can usually tell roughly which European country someone is from by looking at their face.

It doesn't work as well with different parts of Eastern Europe but you get the idea.

Different disease prevalence. Different response to drugs.

Jews for example more likely to have Tay Sachs disease.

Sickle cell disease affects blacks disproportionately.