Rock Doc

We humans go to some trouble so that we can choose which among our domestic animals gets to breed the next generation, thereby over time shaping various lines of animals ranging from types of sheep to varieties of chickens.

Perhaps nowhere is the impact of selective breeding more clear to many of us than with the domestic dog. From ancient breeds like the greyhound and the Dalmatian to more recently derived types like the cocker spaniel, the diversity of dog breeds is a tribute to the power that selecting animals gives us to shape descendants of mated pairs. If you didn’t know it, you might no...