Meeting Abstract
P3.14 Saturday, Jan. 5 Gene expression and ornamental plumage color in the house finch BALENGER, S. L.**; BONNEAUD, C.; EDWARDS, S. V.; HILL, G. E.; Auburn University, AL; Harvard University, Cambridge, MA; Harvard University, Cambridge, MA; Auburn University, AL balensl@auburn.edu
The good genes hypothesis proposes that well-ornamented males possess better than average genes that are passed on to their offspring. Over time, however, variation in genes under sexual selection should be reduced and ultimately fixed in the population, resulting in male ornaments no longer providing accurate information to females. Natural pathogens are predicted to allow for the maintenance of genetic diversity in their host population due to cycles in host-pathogen coevolution. Therefore, honest signaling of genetic quality may persist when a sexually selected trait is an indicator of pathogen resistance and/or immune function. In the house finch (Carpodacus mexicanus), plumage coloration is an important criterion in female choice and pathogens can affect expression of color. House finches infected with the bacterial pathogen Mycoplasma gallicepticum grow feathers that are less red and less saturated than males that are not infected during molt, and males that have redder feather color prior to infection clear disease symptoms faster than their yellower counterparts. To test whether there is a direct relationship between genetic quality and male color, we inoculated wild-caught red and yellow house finches from eastern and western populations with MG, and collected spleen from birds at either 3 or 14 days post-inoculation. Using a previous study, we selected a set of differentially expressed genes and compared RNA expression of each gene to the color of male ornamental plumage. Here we present initial findings from RT-PCR analysis of genes differentially expressed in house finches infected with MG. We discuss results in terms of the relationship between sexually selected plumage color and the expression of genes involved in disease resistance and immune response.
