Extensive pericentric rearrangements in the bread wheat (Triticum aestivum L.) genotype "Chinese Spring" revealed from chromosome shotgun sequence data.
Bottom Line: Based on patterns of their homoeologous arm locations, 551 genes indicated the presence of pericentric inversions in at least 10 of the 21 chromosomes.Available data from deletion bin-mapped expressed sequence tags and genetic mapping in wheat indicated that all inversions had breakpoints in the low-recombinant gene-poor pericentromeric regions.These differences could have significant implications in wheat genome research where comparative approaches are used such as in ordering and orientating sequence contigs and in gene cloning.
Affiliation: CSIRO Agriculture Flagship, St Lucia, Queensland, Australia Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, China.Show MeSH
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Mentions: Genes with locations on 4AS/4BS/4DS could either have been derived from a distal segment of the original 4AS that had not been involved in the complex 4AL/5AL/7BS translocation (the presence of such a fragment had been hypothesized but not yet been proven) (Ma et al. 2013) or represent the transfer of a segment from the modern 4AL to the modern 4AS (fig. 2). Map locations for most of the 25 4AS/4BS/4DS genes on chromosomes 4A and 4D are unknown. Their locations in wheat chromosome 4B, however, indicate that these genes represent at least two separate segments, one derived from the distal chromosome region providing the first evidence of the presence of an original 4AS fragment at the end of the modern 4AS (genes with map locations ranging from 2.86 to 4.98 cM on 4B) and the other from the centromeric region indicative of a rearrangement close to the centromere of chromosome 4A (genes with map locations ranging from 64.89 to 65.7 cM on 4B). Similarly, at least two chromosome segments, one in the centromeric region and one more distally located, were identified that have marker locations 4AL/4BL/4DL. The centromeric segment is characterized by nine genes that map to the region 64.89–65.7 cM on wheat chromosome 4B. These markers indicate the transfer of a segment of the modern 4AS to the modern 4AL. This rearrangement is supported by the location of ESTs BE637507 and BG274862, both of which map to deletion bins C-4AL-12-0.43, C-4BL1-0.71, and C-4DL9-0.31. The existence of a segment of the original 4AL on the modern 4AL arm is indicated by 99 genes with arm locations 4AL/4BL/4DL and genetic map locations in the region 74.63–94.55 cM on 4BL, several of which have supporting deletion bin mapping data (supplementary table S2, Supplementary Material online).Fig. 2.—
Affiliation: CSIRO Agriculture Flagship, St Lucia, Queensland, Australia Triticeae Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu, China.