crossbreed

Bees in Southern California, originally from Europe, started crossbreeding with Africanized bees in the 1990s, said Orange County beekeeper Mike Henderson.

This evolutionary process leads to the formation of ecotypes, i.e., locally adapted "plant breeds" that differ slightly in appearance and may no longer be easily crossbred.

And when distant relatives "crossbreed," this can lead to the emergence of viruses with completely new properties.

However, the initial crossbreeding that created it was done without any intervention from humans.

Using a variety of techniques, including crossbreeding and gene editing, scientists are altering the genomes of vulnerable animals, hoping to arm them with the traits they need to survive.