Evolution of homeobox gene clusters in animals : the Giga-cluster and primary versus secondary clustering
MetadataShow full item record
The Hox gene cluster has been a major focus in evolutionary developmental biology. This is because of its key role in patterning animal development and widespread examples of changes in Hox genes being linked to the evolution of animal body plans and morphologies. Also, the distinctive organization of the Hox genes into genomic clusters in which the order of the genes along the chromosome corresponds to the order of their activity along the embryo, or during a developmental process, has been a further source of great interest. This is known as collinearity, and it provides a clear link between genome organization and the regulation of genes during development, with distinctive changes marking evolutionary transitions. The Hox genes are not alone, however. The homeobox genes are a large super-class, of which the Hox genes are only a small subset, and an ever-increasing number of further gene clusters besides the Hox are being discovered. This is of great interest because of the potential for such gene clusters to help understand major evolutionary transitions, both in terms of changes to development and morphology as well as evolution of genome organization. However, there is uncertainty in our understanding of homeobox gene cluster evolution at present. This relates to our still rudimentary understanding of the dynamics of genome rearrangements and evolution over the evolutionary timescales being considered when we compare lineages from across the animal kingdom. A major goal is to deduce whether particular instances of clustering are primary (conserved from ancient ancestral clusters) or secondary (reassortment of genes into clusters in lineage-specific fashion). The following summary of the various instances of homeobox gene clusters in animals, and the hypotheses about their evolution, provides a framework for the future resolution of this uncertainty.
Ferrier , D E K 2016 , ' Evolution of homeobox gene clusters in animals : the Giga-cluster and primary versus secondary clustering ' Frontiers in Ecology and Evolution , vol 4 , 36 . DOI: 10.3389/fevo.2016.00036
Frontiers in Ecology and Evolution
Copyright © 2016 Ferrier. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Work in the author's lab is funded by BBSRC DTP studentships and the School of Biology, University of St. Andrews.
Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.