Whole-genome sequence of Potamopyrgus antipodarum—a model system for the maintenance of sexual reproduction—reveals a recent whole-genome duplication

Key unanswered questions in biology center on the causes, consequences, andmaintenance of sexual reproduction (“sex”). Genome-driven processes are central to theevolutionary and genetic mechanisms inherent to sex, making genomic resources afundamental part of answering these questions. We present the first genome assemblyfor a species that is uniquely well-suited for the study of (a)sex in nature, Potamopyrgusantipodarum. This New Zealand snail is unusual in featuring multiple separate transitionsfrom obligately sexual to obligately asexual reproduction, leading to the coexistence ofphenotypically similar sexual and asexual forms, a feature that is required to directlystudy the maintenance of sex. These separately derived asexual lineages constituteseparate evolutionary experiments, providing a powerful means of characterizing howthe absence of sex affects genome evolution. Our genome assembly provides criticalsteps towards understanding causes and consequences of sex in this system andimportant resources for the rapidly growing P. antipodarum and molluscan genomicsresearch community. In characterizing this genome, we uncovered unexpected evidencefor a recent whole-genome duplication (WGD) in P. antipodarum. This discovery sets thestage for evaluating processes of rediploidization immediately following WGD andassessing whether WGD might drive transitions to asexuality in P. antipodarum.