The idea that a trait or disease is “in your genes” is a relatively new scientific concept, and it would not have been discovered without the study of countless human genomes. Nowadays there are over the counter DNA test kits that can provide insights into your ancestry as well as genetic risk for disease—but what are the results based on? Genome-wide association studies (GWAS) examine genetic variants—changes in the DNA sequence within a gene—in collections of different individuals to determine how they are associated with a given trait. Some variants are common and benign, such as those that contribute to hair color, while others can cause disease or increase disease risk.
