WHAT makes a population of animals distinct? This is no arcane academic debate. When trying to preserve biodiversity, wildlife managers do not simply look at lists of species: effective conservation also depends on identifying subspecies or distinct populations that merit protection. Otherwise, important populations can go extinct and species become so genetically impoverished that their survival is placed at risk.
Yet no clear criteria exist for defining a subspecies, and there is widespread disagreement about the meaning of a “distinct” population. Molecular techniques ought to be helping by quantifying the genetic relationships between populations and subspecies. In practice, they are…
