FERRIER, D.E.K.; Univ. of Oxford: Homeobox gene clusters in polychaete annelids.

Genes of the Antp-superclass (including Hox, ParaHox and NK genes) are key regulators of development across the animal kingdom. A distinctive feature of these genes is that they tend to be arranged into clusters in the genome. This is typified by the famous Hox gene cluster, but is also apparent with the ParaHox and NK genes. These gene clusters are not mere groups of genes, but rather the organisation of the genes within the clusters seems to be linked to their function – in the Hox cluster there is the phenomenon of Colinearity, whereby the order of the genes along the chromosome corresponds to the order along the embryo�s anterior-posterior axis in which the genes are active. These homeobox gene clusters have so far only been characterised from two of the three major groups of triploblast bilaterian animals: from the Ecdysozoa and Deuterostomia, but not from the Lophotrochozoa. We are using polychaete annelids as our model lophotrochozoan in which to analyse homeobox gene clusters, for comparison to those of ecdysozoans and deuterostomes. This will permit a more robust reconstruction of the bilaterian ancestral condition than is possible from the ecdysozoan-deuterostome comparison alone, and will reveal distinctive patterns of evolution along each of the three main lineages.