Genetics of Morphological Evolution among Closely Related Species
Most phenotypes of evolutionary interest are influenced by many genes. Consequently, understanding the number, phenotypic effect size, and mode of action of genes that contribute to these complex traits is an important challenge for evolutionary biologists. The house mouse provides a fantastic system for studying the genetic basis of phenotypic evolution because wild-derived inbred strains exist, remarkable genetic and genomic resources are available, and much is known about the natural history of wild mice. We are using these tools to dissect the genetic basis of skeletal evolution in house mice. Specifically, we are crossing wild-derived inbred strains from species of house mice that differ in skeletal morphology (Mus domesticus, M. musculus, and M. castaneus) and mapping quantitative trait loci (QTL) that explain these differences. By mapping loci that affect the same traits in crosses among multiple species pairs, we can reconstruct the evolutionary history of these loci.
The classical inbred mouse strains that function as model systems for complex human disease are descended from these wild species of mice. We are collaborating with Dr. Chris Vinyard (Northeastern Ohio Universities College of Medicine) and the Mouse Phenome Database to survey skeletal morphology in 40 of the commonly used inbred strains. Combining these phenotypic data with genome-wide patterns of polymorphism allows us to reconstruct the evolution of morphology in these strains. We are also using these data to ask whether the same loci contribute to morphological differences between the classical strains and morphological variation between wild species.