Ancient whole genome duplications (WGDs) and the additional genetic resources resulting from them have played major roles in the evolution many eukaryotes. In vertebrates, there is strong evidence that two rounds of ancient WGD were followed by a third additional WGD in the teleost fishes – the fish specific genome duplication (FSGD). The role that WGD plays in the evolutionary success of recipient taxa and lineages has been hotly debated for many decades. However, while progress has been made in understanding the origins and mechanisms of the formation of polyploids in many groups, less attention has been devoted to the advantages and/or disadvantages of being a polyploid. This PhD project will investigate two related facets of individual fitness - immune gene diversity (the MHC) and macroparasite burden, in a group of neotropical catfishes (the Corydoradinae) that have undergone multiple WGDs, ranging from ancient paleopolyploid events (~40 mya) to relatively recent duplications (~1-2 mya). The Corydoradinae are widely over South America and comprise more than 170 described species divided into 9 lineages. The group demonstrate multiple genome duplication events (polyploidy) and also exhibit complex mimetic colour pattern relationships1. Using sympatric communities of species (which should theoretically be exposed to the same parasites) that vary in ploidy level, this project will: 1) use next generation sequencing to quantify MHC diversity in taxa that range from diploid to potentially 16x ploid; (2) quantify macroparasite burdens in multiple sympatric communities consisting of diploid and polyploid species (3) investigate the role of additional host-specific factors that may influence macroparasite burdens such as size, age, diet and population demographics. The successful applicant join the group of Dr Martin Taylor who has recently moved to UEA (see 2) and will receive training in next generation sequencing and associated bioinformatic analysis as well as more traditional techniques such as parasitology. There will also be opportunities for conducting fieldwork in South America with Brazilian collaborators.

(i) Alexandrou, M., Oliveira, C, Maillard, M, McGill, R.A.R., Newton, J., Creer, S. and M. I. Taylor. (2011) Competition and phylogeny determine community structure in Müllerian co-mimics. Nature 469:84–88, 2011. DOI:10.1038/nature09660