"For example—oh, what was his name? Fajans, at the U. of Michigan, spent
thirty-two years following five generations of one family. Several dozen of the
hundreds of people he studied had a form of maturity-onset diabetes. Then a 
geneticist, Bell, waded through the family gene pool, searching for similar
areas on chromosomes shared by the family members with diabetes. He found some
markers for the diabetes genes, but it was only a beginning. After three and a
half years of work, they narrowed the choice of three billion base pairs down to
ten million. Good, but not good enough.