Correction: Disentangling the Origins of Cultivated Sweet Potato (Ipomoea batatas (L.) Lam.)

Abstract

Sweet potato (Ipomoea batatas (L.) Lam., Convolvulaceae) counts among the most widely cultivated staple crops worldwide, yet the origins of its domestication remain unclear. This hexaploid species could have had either an autopolyploid origin, from the diploid I. trifida, or an allopolyploid origin, involving genomes of I. trifida and I. triloba. We generated molecular genetic data for a broad sample of cultivated sweet potatoes and its diploid and polyploid wild relatives, for noncoding chloroplast and nuclear ITS sequences, and nuclear SSRs. Our data did not support an allopolyploid origin for I. batatas, nor any contribution of I. triloba in the genome of domesticated sweet potato. I. trifida and I. batatas are closely related although they do not share haplotypes. Our data support an autopolyploid origin of sweet potato from the ancestor it shares with I. trifida, which might be similar to currently observed tetraploid wild Ipomoea accessions. Two I. batatas chloroplast lineages were identified. They show more divergence with each other than either does with I. trifida. We thus propose that cultivated I. batatas have multiple origins, and evolved from at least two distinct autopolyploidization events in polymorphic wild populations of a single progenitor species. Secondary contact between sweet potatoes domesticated in Central America and in South America, from differentiated wild I. batatas populations, would have led to the introgression of chloroplast haplotypes of each lineage into nuclear backgrounds of the other, and to a reduced divergence between nuclear gene pools as compared with chloroplast haplotypes.

Diversity Analysis of Sweet Potato Genetic Resources Using Morphological and Qualitative Traits and Molecular Markers

“…Despite the historical and commercial importance of sweet potatoes, to date, no study has investigated the origin, the conservation, or the genetic background of this species in Italy. On a larger scale, several works have been published [4,5,6,7,8] on the genetic characterization of sweet potato accessions, mainly to investigate the dispersal of New World sweet potato landraces from the center of origin (Tropical America, [9]). One of the main obstacles to the understanding of the dispersal dynamics of sweet potato throughout the world is probably the genetics of this hexaploid species (2 n = 6x = 90) [10], which severely complicates any genomic approach.…”

Genome-Wide Identification and Expression Analysis of Expansin Gene Family in the Storage Root Development of Diploid Wild Sweetpotato Ipomoea trifida

“…Among the 600–700 species of the genus Ipomoea , at least 63 have been recorded as having SR, several of which are edible and some of which are larger than those of sweetpotato; however, I. trifida is not among these 63 species [ 21 ]. On the basis of a phylogenetic analysis together with morphological studies, DNA barcodes and high-throughput sequencing, I. trifida has been determined to be the closest wild relative of sweetpotato, and sweetpotato may have diverged from I. trifida more than one million years ago [ 19 , 20 , 21 ]. Compared with sweetpotato, the diploid I. trifida has much smaller genome size and chromosome number, and the genome structure is also simpler.…”

“…However, the function of other genes in the expansin gene family is still unknown due to the limitation of sweetpotato genome research. I. trifida is the putative progenitor of sweetpotato, and is a species complex with diploids to hexaploids [ 19 , 20 , 21 ]. The diploid I. trifida has a relatively simple genome and has gradually become a model for sweetpotato research, especially with respect to SR formation [ 22 , 23 , 24 , 25 , 26 ].…”

Dispersal, Isolation, and Interaction in the Islands of Polynesia: A Critical Review of Archaeological and Genetic Evidence

“…), bottle gourd (Lagenaria siceraria), breadfruit (Artocarpus spp. ), coconut (Cocos nucifera), kava (Piper methysticum), paper mulberry (Broussoneria papyrifera), sweet potato (Ipomoea batatas), taro (Colocasia esculenta), and ti (Cordyline fruticosa)-are equally problematic in that the data is exclusively from modern or herbarium specimens, with 97% to 21% of published samples from a single island or island group [43,[46][47][48]. Another major study on origins, Burley's [49] synthesis of the polygenesis of Fijian culture and society is founded on the accumulation of evidence that the division between Melanesia and Polynesia has its roots in the differential timing and source of founding populations and post-settlement movements.…”