Biology subjects

Yang, F.-J.

Publications and source records attributed to Yang, F.-J..

2 recordsLinked to original sources

bioRxiv2021

Prevalent sex ratio bias in Caenorhabditis nematodes

Although equal sex ratio is ubiquitous and represents an equilibrium in evolutionary theory, biased sex ratios are predicted for certain local conditions. Cases of sex ratio bias have been mostly reported for single species, but little is known about its evolution above the species level. Here, we surveyed progeny sex ratios in 23 species of the nematode genus Caenorhabditis, including 19 for which we tested multiple strains. For the species with multiple strains, 5 species had female-biased and 2 had non-biased sex ratios in all strains, respectively. The other 12 species showed polymorphic sex ratios across strains. Female-biased sex ratios could be due to sperm competition whereby X-bearing sperm outcompete nullo-X sperm during fertilization. In this model, when sperm are limited allowing all sperm to be used, sex ratios are expected to be equal. However, in assays limiting mating to a few hours, most strains showed similarly biased sex ratios compared to unlimited mating experiments, except that one C. becei strain showed significantly reduced female bias compared to unlimited mating. Our study shows frequent polymorphism in sex ratios within Caenorhabditis species and that sperm competition alone cannot explain the sex ratio bias.

evolutionary biology↗

bioRxiv2020

phiC31 integrase for recombination mediated single copy insertion and genome manipulation in C. elegans

C. elegans benefits from a large set of tools for genome manipulation. Yet, the insertion of large DNA constructs and the generation of inversions is still challenging. Here, we adapted the phiC31 integrase system for C. elegans. We generated an integrated phiC31 integrase expressing strain flanked by attP sites that also serves as a landing pad for integration of transgenes by recombination mediated cassette exchange (RCME). This strain is unc-119(-) so RMCE integrants can be produced simply by injection of a plasmid carrying attB sites flanking unc-119(+) and the gene(s) of interest. Additionally, phiC31 integrase is removed concomitantly with integration, eliminating the need to outcross away the integrase. Integrations are relatively easy to obtain for insert sizes up to ~15 kb. Taking advantage of this integration method we establish a dual color fluorescent operon reporter system to study post-transcriptional regulation of mRNA. Last we show that large chromosomal segments can be inverted using phiC31 integrase. Thus the phiC31 integrase system should be a useful addition to the C. elegans toolkit.

genetics↗