standing genetic variation

An interesting illustration of this might be variety seen in dogs, which are still one species that can reproduce together.

Presumably there was some ur-mutt, where almost all the variations we see today were already there, latent, until humans nudged the balances and blends.

Attempts to systematically domesticate foxes [0] suggest that certain packages of physical traits come along with selecting for calm or friendly behavior.

https://www.pbs.org/newshour/science/domesticated-foxes-gene...