International study shows evolutionary consequences of self-fertilization in plants
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Many plants are self-fertilizing, which means that they act both as the mother and father to their own seeds. This can be a good strategy to guarantee seed set, but in the long run self-fertilization is thought to have negative evolutionary consequences. A new study published in the scientific journal Nature Genetics shows that these negative consequences can arise more rapidly than previously thought.
In the study researchers from Uppsala University together with an international consortium led by researchers at the University of Toronto and the Max Planck Institute for Developmental Biology have sequenced the genome of the plant species Capsella rubella, or Red Shepherd’s Purse. Red Shepherd’s Purse is a young species that has been self-fertilizing for less than 200,000 years. It is therefore especially well suited for studying the early effects of self-fertilization. By contrasting Red Shepherd’s Purse with its outcrossing progenitor the researchers have shown that self-fertilization has already left traces in the genome.
“Our results clearly show that natural selection is relaxed in Red Shepherd’s Purse”, says first author Tanja Slotte who leads a research group at Uppsala University that contributed to the study.
“Theoretically it is expected that natural selection should be relaxed in selfing species, but it has been difficult to support this claim in the absence of large-scale genetic data. The results are important for explaining why ancient self-fertilizing lineages are rare and support the long-standing hypothesis that self-fertilization is an evolutionary dead-end.”