The Australian Centre for Evolutionary Biology & Biodiversity presents Simon Baxter, Ramsay Research Fellow at the University of Adelaide on Friday 15th March 2013.
The seminar is titled ‘Molecular evolution of butterfly mimicry.’ (See abstract below)
Where: B21, Ingkarni Wardli Building, The University of Adelaide
When: Friday 15th March 2013
Heliconius display bright wing patterns that warn predators of distastefulness and also act as mating cues. The diversity of patterns displayed within and between the hundreds of forms is remarkable, as is the convergence between species onto near-perfect mimetic patterns. Recent field studies have identified a group of populations along the eastern slopes of the Andes that are allied to H. timareta and share wing phenotypes with sympatric H. melpomene. Genomic studies have shown that the populations with similar phenotypes also share allelic variation at wing patterning loci, with adaptive introgression across the species boundary providing the most likely explanation for this pattern.
We sequenced a 600 Kb genomic region that regulates diverse red wing pattern phenotypes, using 80 Heliconius samples. Genomic intervals associated with at least three independent red colour pattern phenotypes were resolved using sequence comparisons that grouped similar wing phenotypes, irrespective of species. By comparing the level of nucleotide variation within each colour pattern interval, we estimate the time in generations when introgression events occurred between H. melpomene and H. timareta. Gene exchange after speciation has resulted in the adaptive spread of colour pattern alleles. Here we have identified narrow genomic regions that must act through different cis-regulatory elements of the transcription factor optix, in order to control complex mimetic phenotypes.