What is "homeotic gene"

n. one the genes that are involved in embryologic development

Homeotic genes are genes which regulate the development of anatomical structures in various organisms such as insects, mammals, and plants. This regulation is done via the programming of various transcription factors by the homeotic genes, and these factors affect genes through regulatory genetic pathways.

Mutations in the homeotic genes can occur, leading to what are known as homeotic mutants. These mutants display ectopic placement of body parts (such as antennae growing at the posterior of the fly instead of at the head) or abnormal expression of the homeotic gene. Mutations that lead to these ectopic placements are usually lethal to the organism.