Collaborative Research: Plumage redness and good genes in the House Finch

Harvard University, Cambridge MA

Investigators

Abstract

Male birds display remarkable variation in plumage coloration, and females assess these differences when selecting mates. The rationale for such mate choice is that ornamentation is correlated with genetic quality so that, by choosing colorful males, females obtain good genes for their offspring. Genes contributing to greater disease resistance are quintessential in the natural world because pathogens greatly affect their hosts' reproduction and survival. As a result, "resistance" genes have often been assumed to be the good genes associated with bright coloration. The hypothesis of plumage coloration signaling good genes will be tested first by determining which genes are switched on or off when House Finches are infected with the bacterial pathogen, Mycoplasma gallicepticum. Gene expression will be determined using tools called microarrays that can accurately quantify the increase or decrease in expression of thousands of genes simultaneously. Gene expression patterns will be compared between brightly colored and drably colored male House finches. If the Good Genes Hypothesis is correct, brighter males should show different gene expression profiles than drabber ones. Furthermore, the turning on of specific genes known to play a role in disease resistance will help determine whether plumage coloration is associated with specific good genes. This research is important because it improves understanding of the evolutionary processes that lead to the evolution of disease resistance. Understanding all facets of disease resistance is crucial for predicting and responding to the threats of emerging infectious diseases in wildlife, domestic animals, and humans.