Only if you consider American to describe a particular set of genetics does this question even make sense.
It's not about having the exact same genetics.
For example, it might be about sets of genes or functionally equivalent sets of genes that function in a similar manner despite appearing in members of ostensibly different "races".
The article mentioned that students are chosen for these experiments. Maybe students self-select for having particular genetic sets so you end up with homogenous-enough results that are going to differ radically from the results obtained from genetically isolated groups in other parts of the world.
You start talking about genes, and people panic and worry that you're talking about race. Genes are more complex than that.
It's not about having the exact same genetics.
For example, it might be about sets of genes or functionally equivalent sets of genes that function in a similar manner despite appearing in members of ostensibly different "races".
The article mentioned that students are chosen for these experiments. Maybe students self-select for having particular genetic sets so you end up with homogenous-enough results that are going to differ radically from the results obtained from genetically isolated groups in other parts of the world.
You start talking about genes, and people panic and worry that you're talking about race. Genes are more complex than that.