Genome-wide association studies (GWAS) have identified thousands of genetic variants that are associated with a wide range of diseases. But these studies often fall short of establishing what a genetic variant does to bring about a particular trait or disease. “The challenge has been that many of these variants are difficult to interpret,” said Jesse Engreitz, a former postdoctoral fellow at the Broad Institute of MIT and Harvard and now an assistant professor at Stanford University. Genetic variants are even harder to interpret when they are in regions of the genome that don’t code for proteins, such as in regions called enhancers. These noncoding elements modulate the activity of genes that are often located far away from the enhancer, and they do so differently in different cell types.
