Selfing is the safest sex for Caenorhabditis tropicalis
- Ecole Normale Superieure, France
- New York University, United States
- Northwestern University, United States
- Duke University, United States
- Université Côte d'Azur, CNRS, Inserm, France
- Eastern Michigan University, United States
Abstract
Mating systems have profound effects on genetic diversity and compatibility. The convergent evolution of self-fertilization in three Caenorhabditis species provides a powerful lens to examine causes and consequences of mating system transitions. Among the selfers, C. tropicalis is the least genetically diverse and most afflicted by outbreeding depression. We generated a chromosomal-scale genome for C. tropicalis and surveyed global diversity. Population structure is very strong, and islands of extreme divergence punctuate a genomic background that is highly homogeneous around the globe. Outbreeding depression in the laboratory is caused largely by multiple Medea-like elements, genetically consistent with maternal toxin/zygotic antidote systems. Loci with Medea activity harbor novel and duplicated genes, and their activity is modified by mito-nuclear background. Segregating Medea elements dramatically reduce fitness, and simulations show that selfing limits their spread. Frequent selfing in C. tropicalis may therefore be a strategy to avoid Medea-mediated outbreeding depression.
Data availability
All sequencing reads used in this project are available from the NCBI Sequence Read Archive under accession PRJNA662844. Software code is available from https://github.com/lukemn/tropicalis. All data generated or analysed during this study are included in the manuscript and supporting files. Source data and supplementary files have been provided for Figures 1,2,3,4,5,6,7,9,10,11,12.
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C. tropicalis genomic dataNCBI SRA, PRJNA662844.
Article and author information
Author details
Jacqueline L Jackson
Funding
National Institute of Environmental Health Sciences (ES029930)
- Erik C Andersen
National Institute of Environmental Health Sciences (ES029930)
- Matthew V Rockman
National Institute of General Medical Sciences (GM089972)
- Matthew V Rockman
National Institute of General Medical Sciences (GM121828)
- Matthew V Rockman
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Noble et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Selfing is the safest sex for Caenorhabditis tropicalis
eLife 10:e62587.
https://doi.org/10.7554/eLife.62587
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