Evolution of self-fertilization and outcrossing
What is it about?
Self-fertilization is often thought of as a "dead-end" strategy: the short-term advantages make it unlikely that a selfing species will revert to outcrossing, and the reduced genetic variation produced by selfing make adaptation and diversification less likely. Thus, selfing species will tend go extinct faster and more often than outcrossing species. We used ancestral character state reconstructions to show that the volvocine green algae have repeatedly evolved facultative self-fertilization, self-fertilizing species persist in the long term, and that multiple reversals from selfing to outcrossing have occurred.
Why is it important?
Most of the proposed benefits of sex have to do with outcrossing, or mixing your genes with those of another, genetically distinct, individual. Nevertheless, a lot of species that reproduce sexually do so without outcrossing. This is especially common in plants, where it's called "self-pollination" or just "selfing." Selfing is thought to provide short-term advantages such as the ability to self-fertilize when you are unable to find a mate, but it doesn't provide most of the benefits associated with sex, so it's thought to be a bad strategy in the long term.
The following have contributed to this page: Matthew Herron and Erik R Hanschen
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