WG_HMEL.ME
Heliconius melpomene melpomene Genome sequencing
a consortium we are currently collaborating to sequence the genome of a Heliconius species using a combination of 454 and Illumina sequencing technology, in collaboration with the Baylor Human Genome Sequencing Centre.  See also recent Genomics posts for updates on progress.  Why Heliconius?  A major challenge in evolutionary biology is to identify the genes underlying the diversity of morphologies and adaptations within populations and among species. We would like to know how developmental pathways are modified to produce evolutionary novelty; which genes underlie evolutionary radiations or adaptive change and whether they share particular characteristics or modes of action.  Examples of recent evolutionary novelty are also useful for studying genetic variation in the genome surrounding a locus under strong selection. Strong selection can reduce genetic variation in surrounding regions and might be an important cause of genetic drift . This  signature of selection  is used to detect genes in human disease gene association studies, but we are still lacking empirical studies of the expected pattern under different selection regimes. Butterfly wing patterns are excellent models of phenotypic adaptation, as they have a long history of field studies demonstrating their adaptive value, they are highly diverse even between very closely related taxa, and they are amenable to manipulation studies during development. In particular many species show striking convergence of pattern due to mimicry, which offers an opportunity to study how different species produce the same phenotype: how repeatable is adaptation in different genetic backgrounds?  Heliconius butterflies are a long-standing example of mimicry adaptation in a group that are particularly well suited to this kind of study. The Mullerian co-mimics, H. melpomene and H. erato, are well known for precise mimicry between the two species but also a great diversity of geographic races. Thus, the two species look identical in any one site, but their pattern changes between geographic locations. We have recently found striking evidence for homology between a cluster of tightly linked patterning loci in H. melpomene and a region controlling similar phenotypic effects in H. erato. More surprisingly, the same locus is homologous to a single pattern switch gene in a third species, H. numata. The latter has a very different pattern of diversity with locally polymorphic populations having several divergent morphs flying