At the time the main concern for plant breeders was pollen movement between different strains of crops — if a variety of sweet corn was contaminated by pollen from a popcorn variety, then
the resulting hybrid offspring would produce seeds that were unusable for market purposes or for selecting new varieties.
When a male germ - line chimera is mated to a female germ - line chimera they will have three types of
offspring — pure band - tailed pigeons, band - tail - passenger pigeon
hybrids, and when an engineered sperm meets an engineered egg cell the
result will be a fully formed de-extinct passenger pigeon.