homeobox
A scientist points to a homeobox gene sequence on a large educational diagram.
Noun: A conserved DNA sequence, approximately 180 base pairs long, found within genes that are involved in the regulation of patterns of anatomical development (morphogenesis) in animals, fungi, and plants. These genes control the body plan of an embryo along the head-tail axis by directing the formation of structures in specific segments.
The term "homeobox" specifically refers to the characteristic nucleotide sequence itself. It is a component of a larger functional gene. * The homeobox codes for a protein domain that binds to DNA. * Mutations in the homeobox can lead to major developmental abnormalities. * Scientists identified the homeobox by comparing genes from different species.
- Homeobox gene: A gene that contains a homeobox sequence. This is the complete functional unit, not the "homeobox" itself.
- Hox genes are a well-known cluster of homeobox genes.
- Homeodomain: The 60-amino acid protein domain encoded by the homeobox sequence, responsible for DNA binding.
- The homeodomain allows the protein to regulate target genes.
- Homeotic gene (n): A broader category of genes that control the identity of body parts. Many, but not all, homeotic genes contain a homeobox.
- Hox gene (n): A specific subset of homeobox genes that are arranged in clusters and are crucial for anterior-posterior patterning in animals.
- Homeotic sequence (less common)
The "homeobox" is the defining DNA sequence. It is incorrect to use "homeobox" as a direct synonym for the entire gene or the resulting protein. The precise meanings are: 1. Homeobox: The specific DNA segment. 2. Homeobox gene: The gene containing that segment. 3. Homeodomain: The protein product of the homeobox sequence.
A scientist points to a homeobox gene sequence on a large educational diagram.
- one of various similar homeotic genes that are involved in bodily segmentation during embryonic development