Term for the involvement of several genes in the development of a trait. A trait can be formed by each participating gene alone (isophaenic polygeny) or the genes involved can complement each other (anisophaenic polygeny). Isospecific polygeny is referred to as additive polygeny or polymery when the individual effects of the genes involved (polymer genes) add up.
Polymery can be present as homomerism or heteromerism, depending on whether the effects of the individual genes are quantitatively equivalent or different. In the case of anisophenic polymery, the genes can complement each other equally or exist alongside a main gene.