Hox Genes-Evo devo etc.
<p><img src="/780a23ad-21af-5760-a433-8c58d516cfde.png"/> <b> Hox genes</b> (also known as homeotic genes) are a group of related genes that control the body plan of an embryo along the anterior-posterior (head-tail) axis.<br/>Hox genes are critical for the proper placement of segment structures of animals during early embryonic development (e.g. legs, antennae, and wings in fruit flies or the different vertebrate ribs in humans)</p>
<p>
<img src="/8028d01a-2fda-518f-83ca-a268d5b5ee33.png"/></p>
<p>
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.
Hox genes have a DNA sequence known as the homeobox. The homeobox is a 180 nucleotide-long DNA sequence which codes for a 60 amino acid-long protein domain known as the homeodomain. This works by binding with DNA.</p><p> Hox genes are in gene clusters on the genome</p><p> The order of the loci in the chromosome parallels the order in which the loci are expressed in segments along the body.</p><p> This cluster of master control genes programs the development of all higher organisms.</p><p> The cluster is highly "conserved". It has not changed much over hundreds of millions of years of evolutionary history. Molecular evidence shows that some limited number of Hox genes have existed in the Cnidaria since before the earliest true Bilatera. This means the system evolved before the-Palaeozoic era. </p>
<p>
</p>
<p>
</p>
<p>
</p>
<p>
</p>
<p>
</p>