Genomic Consequences of Asexuality

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Intellectual Merit: Sexual reproduction is more costly than asexual reproduction, yet nearly all organisms reproduce sexually at least some of the time. Why is sexual reproduction so common despite its costs? Are there significant evolutionary consequences of asexual reproduction? What are the effects of sexual reproduction or its absence on the evolution of genes and genomes? Despite decades of study, these and related questions remain unanswered. Established genetic model systems such as fruit flies and yeast have provided important insights into the genetic and genomic consequences of sex and recombination. However, these systems are limited because they do not offer the ability to make direct comparisons between sexual and asexual organisms--and their genomes--from the same natural populations with similar genetic background and environmental history. This project will use a different organism, Potamopyrgus antipodarum, a New Zealand snail, which has both sexual and independently-derived asexual lineages that make it ideally suited to address fundamental evolutionary questions of how genes and genomes evolve in the absence of sexual reproduction. This research will take advantage of the unique strengths of P. antipodarum and extend them to the genomic level, generating novel insights into the genetic consequences of sexual reproduction and its absence. Analyzing sexual and asexual lineages will make it possible to catch mutation accumulation and gene loss in the act. This research will also provide key steps forward in developing P. antipodarum into a powerful model system for many important biological questions, from host-parasite dynamics to ecotoxicology. Since a key unique element of sexual reproduction is the rapid generation of genetically diverse offspring, research outcomes will also illuminate the extent to which the preservation of genetic diversity within populations, species, and ecological communities is integral to the preservation of biological diversity. Broader Impacts: The research will provide numerous opportunities for student training and career development in evolutionary biology, molecular genetics, genomics, and bioinformatics. Effort will be focused on the Biosciences Advantage and SROP/McNair programs, which serve students from historically underrepresented and underserved minority groups with interest in a research career. Collaborations will be initiated with two high schools in inner-city Minneapolis serving primarily underrepresented student groups. Science outreach efforts will be directed towards support and expansion of the local Darwin Day civic group, which is dedicated to organizing events aimed at increasing public scientific awareness, comfort, and literacy, and their efforts to initiate a multi-pronged media consortium.