21039564
not annotated - annotated - LINNAEUS only
High homologous gene conservation despite extreme autopolyploid redundancy in sugarcane.
Modern sugarcane (Saccharum spp.) is the leading sugar crop and a primary energy crop. It has the highest level of 'vertical' redundancy (2n=12x=120) of all polyploid plants studied to date. It was produced about a century ago through hybridization between two autopolyploid species, namely S. officinarum and S. spontaneum. In order to investigate the genome dynamics in this highly polyploid context, we sequenced and compared seven hom(oe)ologous haplotypes (bacterial artificial chromosome clones). Our analysis revealed a high level of gene retention and colinearity, as well as high gene structure and sequence conservation, with an average sequence divergence of 4% for exons. Remarkably, all of the hom(oe)ologous genes were predicted as being functional (except for one gene fragment) and showed signs of evolving under purifying selection, with the exception of genes within segmental duplications. By contrast, transposable elements displayed a general absence of colinearity among hom(oe)ologous haplotypes and appeared to have undergone dynamic expansion in Saccharum, compared with sorghum, its close relative in the Andropogonea tribe. These results reinforce the general trend emerging from recent studies indicating the diverse and nuanced effect of polyploidy on genome dynamics.
Ann file
T1 Species 78 87 sugarcane
N1 Reference T1 Taxonomy:4547
T2 Species 98 107 sugarcane
N2 Reference T2 Taxonomy:4547
T3 Species 109 123 Saccharum spp.
N3 Reference T3 Taxonomy:15819
T4 Species 382 396 S. officinarum
N4 Reference T4 Taxonomy:4547
T5 Species 401 414 S. spontaneum
N5 Reference T5 Taxonomy:62335
#1 AnnotatorNotes T3 TODO check