Or it may be simply that plasticity increases with inter-breeding on a wider basis.
Some of them were half wolf—creatures that were the result of inter-breeding on the part of Athabaskan Indians.
Dorkings degenerate more than any breed by inter-breeding, and rapidly decrease in size.
By inter-breeding hybrids pure types may be got, or reversions, or "an epidemic of variations."
I would not, however, be taken to advocate the inter-breeding of white and black.