[5][6][7] In vertebrates, the genes encoding the class of transcription factors called homeobox genes are found in clusters named A, B, C, and D on four separate chromosomes.

Expression of these proteins is spatially and temporally regulated during embryonic development.

More specifically, it may function in fertility, embryo viability, and regulation of hematopoietic lineage commitment.

Alternatively spliced transcript variants encoding different isoforms have been described.

[9] This article incorporates text from the United States National Library of Medicine, which is in the public domain.