Jacob Cooper, Graduate Student

Hybrid incompatibilities in Drosophila

Species are formed when two populations differentiate so much that their hybrid progeny are unfit. This decrease in hybrid fitness is called a hybrid incompatibility, and at it is the reason that any two species are isolated from one another. Jacob uses the model of Drosophila simulans and Drosophila melanogaster to study this fundamental phenomenon of evolution at the molecular and genetic level.

Drosophila melanogaster and Drosophila simulans are two of the longest studied models for genetics and molecular biology. Despite this, little is known about what genes cause hybrid incompatibilities between them, or how those genes enact their functions. Crossing D. melanogaster females to D. simulans males produces sterile hybrid females, but no hybrid males. Near the beginning of his thesis research, Jacob assisted in a project to map a new hybrid male incompatibility gene. He has been since been working to understand how that gene and others contribute to hybrid male inviability. 


Rapid evolution in mammals

For individuals of a species to maintain homeostasis generation after generation, most genes in the genome need to have mutations purged away so that their function is conserved. However, in nearly every species there are a handful of genes that are under pressure to diversify, and new forms are often favored over old forms. These are rapidly evolving genes, and they often have functions at the interface of host-pathogen interactions, reproductive competition, or regulation of selfish genetic elements. Their patterns of genetic variation can provide insight into some of the most dynamic process in evolution.

Jacob studies patterns of rapid evolution at the genomic scale, where many questions remain about the prevalence of rapid evolution across large gaps of evolutionary time. Recently Jacob has found that ion channels on primate sperm and Drosophila sperm experience similar patterns of rapid evolution, despite being encoded by different genes in taxa separated by millions of years. He is currently working on analyzing patters of rapid evolution by leveraging new data made available by the genomics era.