Collaborative Research: Functional genomics of plumage ornaments in a warbler

University Of Wisconsin-Milwaukee, Milwaukee WI

Investigators

Abstract

One of the grand challenges in animal biology is to understand the influence of genes on the development of phenotypic and behavioral traits. The plumage of birds encompasses a spectacular array of ornamental plumages long appreciated for their beauty, yet we know little about how the color of plumage patches or their size is influenced by genes. It is generally thought that the plumage color of male birds is a signal of quality to females choosing mates. Several hypotheses have now been proposed linking the size and color of plumage ornaments to various physiological and genetic pathways related to health, including those involved in cellular metabolism, growth, oxidative stress and immunity. Any one pathway could provide a general explanation for how bird colors signal quality in males, but these genetic pathways may interact in complex ways that can only be understood using genome-wide analysis techniques. Here the researchers plan to examine these pathways using next generation gene sequencing of the genome of a brightly colored warbler. The types of pigments in this bird (black colored melanin and yellow colored carotenoids) are widespread across species and, thus, will provide a general model for many researchers studying the development of colorful ornaments. As part of the project the researchers will conduct workshops on genomics at local colleges, at an international behavior meeting and, in Belize, for a local zoo and local conservationists. This study will use genomic analyses to test several recent hypotheses for the genetic basis of ornament expression in a warbler, the common yellowthroat. This warbler is one of a few species of birds in which females are known to choose mates based on ornamental traits that are associated with indices of fitness. Interestingly, sexual selection targets different ornaments in different populations of the common yellowthroat. In Wisconsin, females prefer males with larger black masks, whereas in New York females prefer males with larger, more colorful yellow bibs. The investigators have already shown that mask size in Wisconsin and bib color in New York are honest signals of similar aspects of male quality in each population. Based on these results, the investigators plan to use a genomics approach to determine if: 1) elaborate ornaments are related to the expression of genes in growth, immunity and oxidative stress pathways, as predicted by recent hypotheses, and 2) if these traits exhibit molecular parallelism where the same genetic pathways are most closely associated with the ornament preferred by females in each location. To maximize the probability of finding differences and to expand the tests of parallelism, the study will also incorporate geographic comparisons with other subspecies and a closely-related species in Belize, which have larger differences in ornament size and color. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.