Why are HOX genes important?
HOX ( homeobox ) genes are a group of related genes that determine the basic structure and orientation of animals.
HOX genes are critical for the proper placement of segment structures of animals during early embryonic development.
e.g. 1) legs , antennae and wings in fruit flies.
2) different vertebrate ribs in humans.
HOX genes exist as gene clusters on the genome.
This cluster of master control genes programme the development of all higher organisms. This cluster is highly conserved.
HOX genes are a complex of genes , whose proteins bind to the regulatory regions of target genes. The target genes then activate or repress cell processes to direct the final development of the organism.
Humans have a total of 39 HOX genes in cluster on four chromosomes.