Analysis of 41 plant genomes supports a wave of successful genome duplications at the Cretaceous-Tertiary boundary
Ancient whole genome duplications (WGDs) have been reported in most evolutionary lineages. Their attributed role remains a major topic of discussion, ranging from an evolutionary dead end to a road towards evolutionary success, with evidence supporting both fates. Previously, based on dating WGDs in a limited number of plant species, we found a clustering of angiosperm paleopolyploidizations around the Cretaceous-Tertiary (KT) extinction event about 66 million years ago. Here, we revisit this finding, which has proven controversial, by combining genomic sequence information for many more plant lineages and using more sophisticated analyses. We included 38 full genome sequences and three transcriptome assemblies in a Bayesian evolutionary analysis framework that incorporates uncorrelated relaxed clock methods and fossil uncertainty. In accordance with earlier findings, we demonstrate a strongly non-random pattern of genome duplications over time with many WGDs clustering around the KT boundary, and we interpret these results in the context of recent studies on invasive polyploid species suggesting that polyploid establishment is promoted during times of environmental stress. We argue that considering the evolutionary potential of polyploids in the light of environmental and ecological conditions present around the time of polyploidization could mitigate the stark contrast in the proposed evolutionary fates of polyploids.
Vanneste, K., Baele, G., Maere, S., Van de Peer, Y. (2014) Analysis of 41 plant genomes supports a wave of successful genome duplications at the Cretaceous-Tertiary boundary. Genome Res. 24(8):1334-1347 .
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