BBSRC Thematic Group: Frontier Bioscience
Understanding the genetic basis of traits remains central to understanding fundamental biological questions – such as how genetic variation maintained in populations – and to developing genetic interventions for beneficial or pest species.
This project will explore the genetic basis of a colour polymorphism in the aposematic bug Lygaeus simulans. Normally, L. simulans exhibits the red-and-black warning coloration typical of many chemically defended insects. However, we have recently isolated a pale mutant (Balfour et al. 2018). The mutation segregates as a single locus in a strictly Mendelian way, but it is also highly pleiotropic: the pale mutant is associated with variation in longevity, fecundity, body size, mating behaviour, and activity. In addition to these whole-organism phenotypes, we are currently examining proteomic differences between pale and wild-type bugs and measuring differences in resting metabolism.
There are two possible scenarios for explaining these patterns. First, the pale mutant could have arisen in a gene (or regulatory sequence of a gene) that is highly pleiotropic, influencing both colour, aspects of energy allocation, behaviour, and metabolism. Alternatively, the pale mutation could have arisen on one allele of a supergene, i.e. a region of genes under very tight linkage disequilibrium, often associated with chromosome inversions (Black & Shuker 2019). Within the supergene complex would be genes that together control the differences in metabolism and behaviour that we have identified. If this latter scenario is the case, most likely the pale mutation arose long after the formation of the supergene. Indeed, given that we see heterozygote advantage for at least one of our traits, it is possible that a polymorphic supergene has been segregating in this species for a long time, hidden in plain view until a visible marker appeared.
The successful PhD candidate will build on our whole-organism and proteomic work to further characterise the pale mutant and identify its genetic basis. Using whole-genome sequencing techniques and classical genetics, we will test whether we have a single gene or a supergene influencing body coloration and the plethora of associated traits in this species.
The project will be of interest to molecular biologists interested in the genetics of non-model organisms, as well as evolutionary biologists interested in the genetics of adaptive traits.
The project will provide extensive training opportunities in and outside of the lab, including bioinformatics, next-gen sequencing and proteomics, experimental design, insect biology, evolutionary theory, as well as a range of transferable skills, focusing in particular on communication skills. The Shuker Lab has a strong track-record in PhD students progressing into academic and academic-related careers.
Informal enquiries are encouraged, so please contact Dr David Shuker ([email protected]
). Please also visit our website for further information on what we get up to (https://insects.st-andrews.ac.uk
Balfour, V.L., Aumont, C., Dougherty, L.R. & Shuker, D.M. (2018) The fitness effects of a pale mutant in the aposematic seed bug Lygaeus simulans indicate pleiotropy between warning colouration and life history. Ecology and Evolution, 8: 12855-12866.
Black, D. & Shuker, D.M. (2019) Supergenes. Current Biology, 29: R615-R617.