A male pheromone that improves quality of the oogenic germline

Pheromones exchanged by conspecifics are a major class of chemical signals that can alter behavior, physiology, and development. In particular, males and females communicate with potential mating partners via sex pheromones to promote reproductive success. Physiological and developmental mechanisms by which pheromones facilitate progeny production remain largely enigmatic. Here we describe how a C. elegans male pheromone, ascr#10, improves the oogenic germline. Before most signs of aging become evident, C. elegans hermaphrodites start producing lower quality gametes characterized by abnormal morphology, increased rates of chromosomal nondisjunction, and higher penetrance of deleterious alleles. We show that exposure to the male pheromone substantially ameliorates all of these defects and reduces embryonic lethality. ascr#10 stimulates proliferation of germline precursor cells in adult hermaphrodites. Greater precursor supply increases physiological germline cell death, which is required to improve oocyte quality in older mothers. The hermaphrodite germline is sensitive to the pheromone only during a time window, comparable in duration to a larval stage, used by the pre-reproductive adults to assess suitability of the environment for reproduction. Our results identify developmental events that occur in the oogenic germline in response to a male pheromone. They also suggest that the opposite effects of the pheromone on gamete quality and organismal longevity arise from a competition over resource allocation between soma and the germline. Overall design: The study is a two-factor design (two animal ages, and exposure to placebo or ascaroside) sequenced using single-end Illumina reads. Three samples are provided for the each of the 50hr placebo/ascr conditions; there are a total of six samples for each of the 58hr placebo/ascr conditions; half of these were collected concurrently along with the 50hr timepoints, but due to insufficient sequencing depth the 58hr samples were collected and sequenced again