Correlating wing morphology and genetic variation in mimetic butterflies

Mimetic butterflies are an intriguing study object for evolutionary biology, because unrelated lineages have acquired very similar appearances to match their chemically defended models. The Mocker Swallowtail Papilio dardanus, a large butterfly widely distributed in subsaharan Africa, is a particularly striking example, because it expresses different morphological forms that each mimic a different model. From breeding studies it is well known that a single genetic locus controls the expression of different morphs. Here we aim to understand how this control functions on a molecular level. The first step is to obtain more information about the regulatory gene that is the apparent switch determining the colour morph. We have identified a particular gene region and a potential 'candidate' gene that is likely to be the desired portion of the genome, but further proof is needed. Here we employ a novel approach for associating the potential candidate gene with the phenotype, by testing the correlation of particular morphological types with a set of single nucleotide changes in the gene region of interest. This can be done by pooling wild-caught specimens of each kind and testing which of these DNA changes are common to them, yet are different from the others. A quantitative method for DNA sequencing ('pyrosequencing') will be used to test for these differences in DNA of different groups. The method will demonstrate a more widely applicable approach on how to associate obvious differences between living organisms and the genes producing these differences.