Dissecting the evolution of bright wing patterns in tropical butterflies
Supervisors: Prof Chris Jiggins, Dr Owen McMillan (Smithsonian Tropical Research Institute, Panama)
Importance of the area of research:
Speciation and adaptation are the fundamental processes that underlie the biodiversity of our planet. The Heliconius butterflies offer an excellent opportunity to gain insights into the genetic architecture of adaptation through their wing patterns that are locally adapted for mimicry and sexual selection. In particular, we understand how natural selection acts on wing patterns via both mimicry theory and experiments in the rainforest, as well as through behavioural assays of sexual behavior. Thus we have the potential to understand evolutionary processes on a single trait from natural selection in the wild through to the identifying specific mutations underlying the evolution of mimicry. The same loci are known to repeatedly control adaptive change across butterflies and moths, which raises the question of why particular genes are repeatedly targeted by natural selection.
The project will address the developmental basis and ecological importance of adaptive wing patterning differences between species. We have recently identified a novel gene controlling patterns called cortex, that controls species differences between closely related species such as H. melpomene and H. cydno, as well as evolution of the melanic form of the famous peppered moth. The project will address the evolutionary history and functional basis for how this gene acts to control yellow wing patterns. cortex is a member of a family of cell cycle regulators which makes it an unlikely candidate for a wing pattern gene.
What the student will be doing:
You will analyse next-generation sequencing data for large populations of butterflies that differ in their wing patterns, looking for associated genetic variants that are putatively causal for different wing patterns. This will allow analyses of the evolutionary history of these wing regions, and will target experiments to test the function of these variants using CRISPR gene knockouts and enhancer element manipulation experiments. The project will therefore combine analysis of Illumina sequence data for population genetic analysis with developmental biology studies of the function of wing patterning genes. This is exciting because of novel tools: the developmental differences in wing pattern between closely related species can now be studied using newly developed CRISPR techniques. The precise focus of the work will depend on the interests of the candidate.
The position would be suitable for anyone with a broad interest in evolution and development.
Training to be provided:
Training will be provided in next generation sequencing and data analysis, in laboratory techniques for analysis of gene expression and manipulation of wing patterning genes using CRISPR. The student would also learn ecological field techniques for collection and study of butterflies in the rainforest. This multidisciplinary study would equip a student well for a future career in a wide range of areas of biology.
Nadeau, N. J. et al. 2016. The gene cortex controls mimicry and crypsis in butterflies and moths. Nature 534, 106–110
The Heliconius Genome Consortium 2012. Butterfly genome reveals promiscuous exchange of mimicry adaptations among species. Nature 487, 94–98.
Naisbit, R. E., Jiggins, C. D. & Mallet, J. 2003. Mimicry: developmental genes that contribute to speciation. Evol Dev 5, 269–80.