The idea of gene exclusion theory centers around the concept that specific genes are either active or inactive within a given organism. This theory has spawned several related terms to help researchers describe and understand the underlying mechanisms behind gene expression. One such term is allelic exclusion, which describes the phenomenon of only one version of a gene being active at a time. Another related term is epigenetic silencing, which refers to chemical modifications that prevent certain genes from being expressed. Additionally, the concept of haploinsufficiency describes cases in which only one copy of a gene is insufficient for proper function, while gene redundancy describes cases in which multiple genes perform the same function.