Melanin Sexual Traits: Linking Parasites to Gene Expression
Female preferences for male sexual traits, such as bright coloration, are thought to be adaptive because male traits provide information to females. Melanin-based color traits are traditionally thought to be under strict genetic control, which makes it unclear how they can serve as an honest indicator of male quality. However, condition-dependence for some melanin traits may occur during early development. If so, trait variation may provide information about an individual’s developmental history to females.
In collaboration with Dr. Joanna Hubbard, we have shown that variation in melanin-based color in barn swallows is due almost entirely (~70%) to differences in early environment. With only about 17% of color expression explained by additive genetic variation. The color that individuals develop as fledglings predicts their color as breeding adults, despite repeated molting of feathers.
This project will identify gene expression differences associated with color variation by cross-fostering eggs and manipulating mites to tease apart the roles of genes and environmental quality. RNA expression will be quantified from developing feather tissue to understand how early environment interacts with genes in the melanin pathway to influence the life-long expression of a melanin-based signal.
This research will have important implications for understanding the gene by environment interactions during the early developmental period for melanin-based ornamental traits, and thus, information that females gain by using these traits.
-(November 2017) First RNA extractions from feather tissue!
-(October 2017) RNA in hand for the first barn swallow reference transcriptome
- (Summer 2016) Field experiment complete
Special thank you to my amazing 2016 field crew: Sheela Turbek, Kelley McCahill, Mara Hernandez, Will Dube, Clair Mastrangelo, Kim Greene, Dan Tomlin, and Heidi Reeg.