The Accumulation of Deleterious Mutations as a Consequence of Domestication and Improvement in Sunflowers and Other Compositae Crops

For populations to maintain optimal fitness, harmful mutations must be efficiently purged from the genome. Yet, under circumstances that diminish the effectiveness of natural selection, such as the process of plant and animal domestication, deleterious mutations are predicted to accumulate. Here, we...

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Bibliographic Details
Published in:Molecular biology and evolution 2015-09, Vol.32 (9), p.2273-2283
Main Authors: Renaut, Sebastien, Rieseberg, Loren H
Format: Article
Language:English
Subjects:
Animal breeding
Asteraceae - genetics
Chromosomes, Plant - genetics
Crop improvement
Crops
Crops, Agricultural - genetics
Domestication
Flowers & plants
Gene Frequency
Genetic diversity
Genetic Enhancement
Genome, Plant
Genomes
Helianthus - genetics
Mutation
Mutation Rate
Natural populations
Plant Breeding
Polymorphism
Recombination, Genetic
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Summary:For populations to maintain optimal fitness, harmful mutations must be efficiently purged from the genome. Yet, under circumstances that diminish the effectiveness of natural selection, such as the process of plant and animal domestication, deleterious mutations are predicted to accumulate. Here, we compared the load of deleterious mutations in 21 accessions from natural populations and 19 domesticated accessions of the common sunflower using whole-transcriptome single nucleotide polymorphism data. Although we find that genetic diversity has been greatly reduced during domestication, the remaining mutations were disproportionally biased toward nonsynonymous substitutions. Bioinformatically predicted deleterious mutations affecting protein function were especially strongly over-represented. We also identify similar patterns in two other domesticated species of the sunflower family (globe artichoke and cardoon), indicating that this phenomenon is not due to idiosyncrasies of sunflower domestication or the sunflower genome. Finally, we provide unequivocal evidence that deleterious mutations accumulate in low recombining regions of the genome, due to the reduced efficacy of purifying selection. These results represent a conundrum for crop improvement efforts. Although the elimination of harmful mutations should be a long-term goal of plant and animal breeding programs, it will be difficult to weed them out because of limited recombination.
ISSN:0737-4038
1537-1719
DOI:10.1093/molbev/msv106