Congratulations to Paul Jay and Mathieu Chouteau for their amazing study now published in Nature Genetics !
The chromosomal inversions bringing great mimicry benefits in Heliconius numata are full of deleterious mutations and insertions of transposable elements. Individual with a homozygous inversion genotype shave very poor larval survival. This means those inversion only bring their mimicry advantage when heterozygous. Therefore, selection caused by these deleterious effects maintains the standard (non-inverted) arrangements in the population, and balances the amazing wing-pattern polymorphism observed.
This illustrates the dual effect of recombination suppression associated with inversions: they lock together beneficial mutations, forming greatly favourable haplotypes, but are also prone to capturing and accumulating deleterious variation, acting against their fixation. This could be a very general mechanism underlying inversion polymorphisms throughout the tree of life.
Nature Genetics. doi:10.1038/s41588-020-00771-1
Read online: https://rdcu.be/cebgl
