Sean’s area of specialization is microbial evolution. By using relatively simple organisms, he aims to elucidate general principles that govern evolution and focuses on understanding the genetic basis of adaptation to understand how genes and entire genomes evolve and respond to selection. To investigate these evolutionary questions, he employs experimental evolution: the continual propagation of microbes under defined, well-controlled conditions. With the advent of next-generation sequencing, he is identifying and characterizing the specific mutations that occur and drive evolution. By evolving hundreds of populations founded from a common ancestor, he can investigate concepts such as the repeatability of evolution.
Investigation of evolutionary concepts has led Sean to study several organisms including yeast, bacteria, and viruses. He’s interested in understanding the variables that influence evolution, such as mutation rate, genome size, ploidy, standing variation, genetic background, and environmental variability/consistency. His study of microbial evolution is often multidisciplinary – drawing from the fields of evolutionary biology, microbiology, genetics, molecular biology, cellular biology, etc.