We aim to understand how the diversity of form in the animal kingdom evolved. The focus of our research is the connection between the evolution of animal genome organisation and development, with a particular concentration on the homeobox-containing genes. The Hox gene cluster is established as a corner-stone of Evolutionary Developmental Biology, but much about the evolution of its organisation and mode of operation remains unknown. Also the Hox cluster is not unique as a homeobox gene cluster controlling animal development, further clusters being the ParaHox and NK clusters, all of which evolved within larger arrays of homeobox genes (the Mega-cluster and Super-Hox cluster). We utilize a variety of organisms in our research (including amphioxus, sea squirts, polychaetes and priapulids), chosen from key points in the phylogeny of the animals to enable reconstruction of the ancestral conditions at major nodes in the animal kingdom; the origin of bilaterians, protostomes, deuterostomes, chordates and vertebrates. 

lab website: https://edge.wp.st-andrews.ac.uk/

Research Interests and current projects.

Evolution of the homeobox gene content of chordates.

The recently sequenced genomes of amphioxus (Branchiostoma sp.), a basal lineage of chordates, are proving to be immensely valuable for revealing characteristics of the organisation of the genomes of the chordate and vertebrate ancestors. Amphioxus has retained the full complement of homeobox gene families that are inferred to have been present in the chordate ancestor. Other chordate lineages have lost some of these gene families. Amphioxus thus provides us with a system with which to understand how these important developmental control genes have been involved in the evolution of the animal lineage containing ourselves.

Evolution of bilaterian animal Hox cluster organisation.

The Hox gene cluster patterns the anterior-posterior axis of bilaterian animals. In animals such as mice the organisation of the genes within the cluster is intimately associated with how the genes are regulated and function during embryogenesis. In other lineages, such as flies, nematodes and urochordates there is no such constraint on cluster maintenance, and the Hox clusters in these animals have broken apart. In order to understand the role that the Hox cluster has had in animal evolution it is imperative to discover the organisation of the cluster in a wide variety of lineages and the mechanisms regulating the genes in these diverse taxa. We are attempting to characterise the Hox clusters of several lineages of supposedly less-derived animals (amphioxus, polychaetes and priapulids) as a means to understanding the ancestral forms of the cluster across the bilaterians.

Evolution of chordate ParaHox gene regulation.

The ParaHox gene cluster is the evolutionary sister to the Hox gene cluster. It has so far only been characterised in chordate taxa, where it also seems to play a role in patterning aspects of the anterior-posterior axis of embryos like its Hox sister. We are investigating how the ParaHox genes are regulated in the basal chordate lineages of amphioxus and sea squirts as a means to understand the fundamental mechanisms controlling these genes in chordates.

Pomatoceros embryology and genome evolution.

It is now clear that polychaetes can provide us with a model system that is much less derived from the ancestral bilaterian condition than are more traditional model systems within the protostomes, such as flies and nematodes. The keelworm, Pomatoceros, is a tube-dwelling, intertidal polychaete that is widespread around the British Isles and is readily accessible for molecular and embryological work. We are studying the embryogenesis of this annelid for comparative purposes and are beginning to investigate the organisation and expression of its developmental genes, particularly the homeobox genes.

Polychaete ParaHox genes.

To understand the role that the ParaHox genes may have played in animal evolution, and whether they have been as vital as the famous Hox genes, their organisation and expression must be understood in a much greater variety of taxa than have currently been investigated. In particular flies and nematodes are of limited value in this endeavour since they have broken up the ParaHox cluster and lost some of the genes. Alternative protostome models are required, such as the polychaetes, which have retained all three ParaHox genes.

Evolution of the organisation of the ANTP-class of homeobox genes.

The clustered organisation of many homeobox-containing genes can have functional implications, as with the Hox cluster, but can also reveal the evolutionary history of these important developmental control genes as well as the evolutionary dynamics of animal genomes. Patterns of gene origin, gene loss, linkage and clustering are being revealed by analysis of the genomes of representative taxa from across the Bilateria.