The evolution of serial homology: a case study with nymphalid butterfly eyespots

Yale University, New Haven CT

Investigators

Abstract

Antónia Monteiro and William Piel Proposal number: IOS-0818731 "The evolution of serial homology: a case study with butterfly eyespots." The bodies of complex organisms have been found to reuse developmental structures, such as teeth, vertebra, and ribs, in order to build "serially" repeated parts or processes. This composite or modular design suggests that certain genetic programs are redeployed multiple times in different places during the developing embryo. It remains to be understood how such modules come to be redeployed over the course of evolutionary diversification. This project aims to explore the evolutionary and developmental origin of complex repeated structures by studying serially-repeated "eyespot" patterns in the wings of butterflies. The researchers will assemble a large phylogenetic tree of nymphalid butterfly species, photograph and code their wing patterns with respect to the presence or absence of spots or eyespots, and use comparative methods to infer how eyespots evolved. In addition, the evolution of the eyespot gene developmental "network" will be investigated by monitoring the expression of four candidate network genes in twenty species chosen on the basis of phylogenetic distribution of wing pattern evolution. This project has considerable educational Broader Impacts over a wide range of educational levels, supporting a graduate student, postdoc, and several undergraduate work-study students. Moreover, several New Haven high school student researchers will be involved through "Evolutions", the Peabody Museum's outreach program to city youth. This project will also generate a publicly accessible high-resolution image database of butterfly species (ca. 8,000 images from 1,000 nymphalid species), a large phylogeny of nymphalids, and the first database for gene expression images in the Lepidoptera. In addition, interactive web-accessible animations will be produced and incorporated into the exhibits of the Peabody Museum. This software will illustrate the diversity of nymphalid wing patterns and will animate the evolution of eyespot changes on phylogeny. This exhibit will introduce the public to the diversity and evolution of wing patterns, the evolution of individuation of repeated modules, and the evolution of morphological novelties such as eyespots.