Evolution of sperm competition: Natural variation and genetic determinants of Caenorhabditis elegans sperm size

BioRxiv : the Preprint Server for Biology
Clotilde GimondChristian Braendle


Sperm morphology is critical for sperm competition and thus for reproductive fitness. In the male-hermaphrodite nematode Caenorhabditis elegans, sperm size is a key feature of sperm competitive ability. Yet despite extensive research, the molecular mechanisms regulating C. elegans sperm size and the genetic basis underlying its natural variation remain unknown. Examining 97 genetically distinct C. elegans strains, we observe significant heritable variation in male sperm size but genome-wide association mapping did not yield any QTL (Quantitative Trait Loci). While we confirm larger male sperm to consistently outcompete smaller hermaphrodite sperm, we find natural variation in male sperm size to poorly predict male fertility and competitive ability. In addition, although hermaphrodite sperm size also shows significant natural variation, male and hermaphrodite sperm size do not correlate, implying a sex-specific genetic regulation of sperm size. To elucidate the molecular basis of intraspecific sperm size variation, we focused on recently diverged laboratory strains, which evolved extreme sperm size differences. Using mutants and quantitative complementation tests, we demonstrate that variation in the gene nurf-1 - previously sho...Continue Reading

Related Concepts

Sperm Cell
Caenorhabditis elegans
Complement Assay

Related Feeds

BioRxiv & MedRxiv Preprints

BioRxiv and MedRxiv are the preprint servers for biology and health sciences respectively, operated by Cold Spring Harbor Laboratory. Here are the latest preprint articles (which are not peer-reviewed) from BioRxiv and MedRxiv.