Dr. Asher Cutter and his research team are studying the genetic basis of evolutionary change. His research is focused on heritable changes through time with causes that are at the interface of natural selection and non-adaptive evolutionary forces, and involves the application of population genetic and molecular evolutionary theory. The variation in breeding system among Caenorhabditis species coupled with C. elegans' history as a model organism for genetics, genomics and development, provides a powerful, novel system for informing the understanding of the evolution of traits relevant to behaviour, physiology and ecology. A combination of approaches are used in the laboratory including computational analysis, molecular biological methods, experimental approaches, and construction of mathematical and simulation models. Reproduction is the primary metric of organismal fitness and, therefore, understanding variation in the mode of reproduction and its effects within and among species constitutes a central theme in biology. Dr. Cutter and his team have quantified nucleotide polymorphisms in samples of three species: C. elegans, C. briggsae, and C. remanei. C. remanei populations are comprised of females and males (i.e. gonochoristic), whereas the other two have self-fertile hermaphrodites and males (i.e. androdioecious). The androdioecious species have nearly 20-fold lower levels of genetic variation than the gonochorist, consistent with extensive inbreeding by self-fertilization. The Cutter laboratory is also involved in a new collaborative project which aims to sequence entire genomes of multiple individuals in order to characterize genome-wide nucleotide polymorphisms. Using both genome-scale and population-based perspectives, the various research groups are seeking to understand how even extremely weak natural selection can alter patterns of DNA sequence in genomes. This involves integration with genome-wide gene expression data and RNAi-based functional inference about genes.