I think they call that phenotypes, one parent instead of 2. Photoperiods are usually stabilized by back crossing them to a parent or a seed from the same batch so over time so the phenotypes are reduced.

Once they are stabilized Fem photoperiod seeds are generally crossed back to themselves so the gene pool is even smaller, and if you keep making fem seeds from fem seed plants the gene pool continues to get a little smaller and they also loose resistance to disease and start getting other less desirable traits. I think that is one of the reasons its best to cross breed regular seeds.

To make an auto flower strain a stabilized photoperiod is crossed with a ruderalis cannabis plant, that I assume is stabilized, and then stabilized by some sort of black magic voodoo shit we dont want to know about. Think about it, ruderalis all come from Russia, auto flowers are all part of the invasion plan, I am sure they are already crossing Russian strains with Chinese strains to complete the plan. So to me buying and growing auto flowers is just plain unamerican.