This is an area where white privilege is real. We are increasingly able to determine risk scores for conditions that might develop later in life, and the large majority of the research subjects have been of North European ancestry. The studies have been done by Americans, Scandinavians, Dutch, etc, and a very large UK Biobank, but consider the motivations of all. Pharmaceutical and other companies have some interest in pure or general research, but mostly they want to be able to develop products for people who might buy them. Where do university labs get their subjects? Governments want to help their own people. 80% of sampling worldwide is Northern European.
To understand why this matters, we usually take height as an example of a polygenic trait. There have been many SNP’s (smallest units) found to be “associated with” height. Even though they only have enough to account for 15% of the variance at this point, it was enough to predict that Shawn Bradley would be well above-average in height from his DNA alone. (Former NBA. 7’6″) But all of these discoveries are from Northern European samples. When you run the same tests on people of African descent, they show very few of those SNPs associated with height. They have so few, in fact that the test will predict that they are very short indeed, less than five feet, even if they are seven feet tall. Africans have different genes making them taller. A word on the side about these many genes that contribute to height. They are not so much of the form “make the shinbone a little longer,” as more general health items such as digestion and energy conversion, or when hormones activate and when they stop. A fair number may be primarily prenatal influence.