Cassava haplotype map highlights fixation of deleterious mutations during clonal propagation
Review statusPeer Review
MetadataShow full item record
Ramu, P., Esuma, W., Kawuki, R., Rabbi, I.Y., Egesi, C., Bredeson, J.V., ... & Lu, F. (2017). Cassava haplotype map highlights fixation of deleterious mutations during clonal propagation. Nature Genetics.
Permanent link to cite or share this item: http://hdl.handle.net/10568/81024
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.
Article purchased; Published online: 17 April 2017