Whole-Genome Duplication and Plant Macroevolution

WGD events continue to be discovered throughout plant systematic diversity as a consequence of genome sequencing programs. The absolute timing of WGD events remains poorly constrained and poorly understood, but many hypotheses regarding the role of WGD in plant evolution depend on precise estimates. The role of WGD in facilitating diversification has a strong theoretical basis but remains to be rigorously tested, and WGD in species-poor lineages cannot be ignored. WGD as a driver of plant morphological diversity is an appealing hypothesis, but requires a framework which can quantify morphological variation between lineages and through time. Whole-genome duplication (WGD) is characteristic of almost all fundamental lineages of land plants. Unfortunately, the timings of WGD events are loosely constrained and hypotheses of evolutionary consequence are poorly formulated, making them difficult to test. Using examples from across the plant kingdom, we show that estimates of timing can be improved through the application of molecular clock methodology to multigene datasets. Further, we show that phenotypic change can be quantified in morphospaces and that relative phenotypic disparity can be compared in the light of WGD. Together, these approaches facilitate tests of hypotheses on the role of WGD in plant evolution, underscoring the potential of plants as a model system for investigating the role WGD in macroevolution. Whole-genome duplication (WGD) is characteristic of almost all fundamental lineages of land plants. Unfortunately, the timings of WGD events are loosely constrained and hypotheses of evolutionary consequence are poorly formulated, making them difficult to test. Using examples from across the plant kingdom, we show that estimates of timing can be improved through the application of molecular clock methodology to multigene datasets. Further, we show that phenotypic change can be quantified in morphospaces and that relative phenotypic disparity can be compared in the light of WGD. Together, these approaches facilitate tests of hypotheses on the role of WGD in plant evolution, underscoring the potential of plants as a model system for investigating the role WGD in macroevolution. sometimes termed fractionation, this is the period following WGD whereby through rearrangement, silencing, and loss of DNA the genome returns to a diploid expression pattern. an n-dimensional multivariate space describing phenotypes, where points represent taxonomic units and the distances between them their (dis)similarities. following gene duplication, one copy of the gene takes on a novel function while the other copy continues to perform the previous function. two genes related by descent, typically with similar sequences, are homologs. If they share a 1:1 relationship between species, they are orthologs. If they deviate from this 1:1 relationship as a result of a duplication event, they become paralogs. Paralogs that have derived specifically from a WGD event are termed ohnologs, after Susumu Ohno. following gene duplication, each duplicate performs part of the original function, and in combination both maintain the original function of the gene.