Knowing where our great-great-great-grandparents and beyond came from is more than a genealogical curiosity. It is giving geneticists a powerful tool for understanding the genetic basis of diseases such as multiple sclerosis, schizophrenia, diabetes and prostate cancer.
These and other diseases have been difficult nuts to crack because they are caused not by a single genetic flaw but have multiple genetic and environmental causes. This makes the links between gene and disease subtle and hard to find. In fact, it has been virtually impossible until now.
David Reich, a geneticist at Harvard Medical School, and his colleagues have now found…
