Dissertation Research: Geographic variation in Dmrt1 in the North American green frog

Yale University, New Haven CT

Investigators

Abstract

This proposal investigates the processes that determine if an embryo becomes a male or female. These processes can differ widely among species, but other features are more conserved between species. Previous work by the researchers showed that the North American green frog and humans share portions of the genome that are important for determining whether an embryo becomes a male or female. Importantly, the researchers discovered that the gene DMRT1, which is critical for human male gonads to develop as normal testes, is also important in green frog development. The researchers also noted widespread abnormalities in green frog development in suburban neighborhoods. This might indicate that human-derived contaminants interfere with how frogs develop. That work was conducted on green frogs in Connecticut. However, green frogs range across half of the United States and parts of Canada, and variation occurs across that range. In addition, work in one European and one Japanese frog species shows variation among populations across the species' range. This project will study the genomic variation in the gene DMRT1 and other genomics regions linked to development in green frogs across the United States. This project will substantially advance our understanding of how variable the genetic basis of development is across a large geographic area. It will also begin to show the extent to which environmental conditions across the country impact frog development. The work will be distributed to the public in a variety of ways including online blogs and guest lectures for K-12 teachers. Using tissue samples collected from male and female green frogs from representative regions across the species' range, the researchers will test for geographic variation in allele frequencies and linkage for DMRT1. Additionally, the researchers will test whether a set of genetic markers shown to be linked with particular chromosomes specific to males and females are similarly linked across the species range. Geographic areas with varying degrees of this linkage, either for DMRT1 or the other markers, will indicate regions of the species' range where environmental conditions are more likely to influence the processes driving whether an embryo becomes male or female.