Let's take white and black people for example because it's easier and funnier that way. Contrary to the popular belief all humans aren't the same when we talk about the genetic structure of various people.
Now let's look at cellular structure of a black person and white person. White people have pheomelanin which has sulfur at it's core. Black people have eumelanin which has selenium at it's core. Why is this important? Melanin is a chemical key to life.
Melanin goes beyond skin color. All the cells in the human by require melanin to function properly. Knowing this we can move on to discuss about how pheomelanin (Caucasian melanin) has sulfur at it's core. This is why white people are able to digest, diary and meat better than people of african descent because sulfur is an acid. So right there that's one major gentical difference between races to refute your point. It's a lot more. If you respond be do so with sources of your information because what you said is scientifically wrong.
Sources.
Melanin: What makes Black People Black by Dr Llaila Afrika
Lactose intolerance seems linked to ancestral struggles with harsh climate and cattle diseases, Cornell study finds | Cornell Chronicle
Melanin - Wikipedia, the free encyclopedia
Sulfur is not an acid, brehski.