Mallon, E. | bioRxiv Science

bioRxiv2019

Evidence of capacitation in the parasitoid wasp, Nasonia vitripennis and its potential role in sex allocation

The allocation of resources to the production of one sex or another has been observed in a large variety of animals. Its theoretical basis allows accurate predictions of offspring sex ratios in many species, but the mechanisms by which sex allocation is controlled are poorly understood. Using previously published data we investigated if alternative splicing, combined with differential expression, were involved with sex allocation in the parasitoid wasp, Nasonia vitripennis. We found that sex allocation is not controlled by alternative splicing but changes in gene expression, that were identified to be involved with oviposition, were shown to be similar to those involved in sperm motility, and capacitation. Genes involved in Cholesterol efflux, a key component of capacitation, along with calcium transport, trypsin and MAPKinase activity were regulated in ovipositing wasps. The results show evidence for regulation of sperm motility and of capacitation in an insect which, in the context of the physiology of the N. vitripennis spermatheca, could be important for sex allocation.

evolutionary biology↗

bioRxiv2019

In silico identification of a molecular circadian system with novel features in the crustacean model organism Parhyale hawaiensis

The amphipod Parhyale hawaiensis is a model organism of growing importance in the fields of evolutionary development and regeneration. A small, hardy marine crustacean that breeds year-round with a short generation time, it has simple lab culture requirements and an extensive molecular toolkit including the ability to generate targeted genetic mutant lines. Here we identify canonical core and regulatory clock genes using genomic and transcriptomic resources as a first step in establishing this species as a model in the field of chronobiology. The molecular clock of P. hawaiensis lacks orthologs of the canonical circadian genes cryptochrome 1 and timeless, in common with the mammalian system but in contrast to many arthropods including Drosophila melanogaster. Furthermore the predicted CLOCK peptide is atypical and CRY2 shows an extended 5 region of unknown function. These results appear to be shared by two other amphipod species.

molecular biology↗