genetic diversity

Lack of genetic diversity can have dire consequences: illness, early death, even extinction for some species. A couple of cases in point — dogs and coffee — seem otherwise unrelated. But both can suffer deleterious effects because of uniform gene pools. But in both cases, genetic engineering could help.
After five years of living in New York, I have gotten used to just about everything this city brings. With one exception: rats. New research on the genetic diversity of these true New Yorkers shows that they tend to stay local. In fact, it's rare that they even move off of the block where they were born.