JTW's Evolutionary Origins - Author: Prince, Victoria
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Evolution of the HOX Cluster
"The evolutionarily conserved Hox genes encode transcription factors implicated in setting up embryonic regional identity along the anteroposterior (AP) axis. Hox genes have been found in all metazoan phyla tested, and differences in their organization and deployment are thought to play a pivotal role in producing variant body patterns. Diagnostic features of Hox genes are:(1) the conserved homeobox sequence that encodes a 60 amino-acid DNA binding homeodomain, and
(2) clustered organization within the genome.
In the invertebrate phyla Hox gene number is variant, but available data suggest that single Hox clusters are the norm. However, the origins of vertebrates are believed to have been accompanied by genome duplication events, and this is reflected by the presence of multiple Hox clusters in the vertebrates. Thus, while the cephalochordate Amphioxus has a single Hox cluster, there are four clusters in tetrapods such as mouse, human and chick. Availability of duplicate Hox genes has presumably allowed scope for duplicates to take on new roles during evolution; hence cluster duplication has been correlated with increased complexity of body plan."
(Prince, 2002)
- Prince, Victoria
- Sinauer Associates
- QL 955.G48 2002
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