seedcorn
Garden Master
It’s been way too many decades since genetic classes. There are a given number of chromosomes that make a sheep a sheep vs being a tree. Then within the chromosomes are genes with recessive or dominant effects as well as interactions between genes and modifiers. There are millions of combinations. What breeders play with are genes and their interactions. Environmental pressures can change their appearance which is what most of us pick for. When u realize there are millions of possible outcomes, it’s easy to see why keeping a line exactly the same is impossible.