The approach to studying a complex trait is much more difficult because we need large numbers of families with many affected individuals. So it's a massive-scale, genetic search, compared to how we find single genes.
ANNOUNCER: Researchers have begun to use something called a gene chip to study many genes at once.
ANGELA CHRISTIANO, PhD: One of the most powerful tools of modern genetics is known as a gene chip or microarray. In contrast to looking for one gene at a time, the microarray lets us look at global changes in gene expression, 12,000 to 30,000 all at one time. This greatly multiplies the effectiveness of which we can study conditions like male pattern hair loss.
ANNOUNCER: And with the knowledge of how genes contribute to hair loss, scientists say they will be better able to develop drugs to combat baldness.