Cassava haplotype map highlights fixation of deleterious mutations during clonal propagation
Cassava (Manihot esculenta Crantz) is an important staple food crop in Africa and South America; however, ubiquitous deleterious mutations may severely decrease its fitness. To evaluate these deleterious mutations, we constructed a cassava haplotype map through deep sequencing 241 diverse accessions and identified >28 million segregating variants. We found that (i) although domestication has modified starch and ketone metabolism pathways to allow for human consumption, the concomitant bottleneck and clonal propagation have resulted in a large proportion of fixed deleterious amino acid changes, increased the number of deleterious alleles by 26%, and shifted the mutational burden toward common variants; (ii) deleterious mutations have been ineffectively purged, owing to limited recombination in the cassava genome; (iii) recent breeding efforts have maintained yield by masking the most damaging recessive mutations in the heterozygous state but have been unable to purge the mutation burden; such purging should be a key target in future cassava breeding.
| Main Authors: | , , , , , , , , , |
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| Format: | Journal Article biblioteca |
| Language: | English |
| Published: |
Springer
2017-06
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| Subjects: | genomics, plant genetics, population genetics, cassava, deleterious mutations, haplotype map, clonal propagation, |
| Online Access: | https://hdl.handle.net/10568/81024 https://doi.org/10.1038/ng.3845 |
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