bio

Polyploidy

Carrying more than two chromosome sets, usually through duplication of the entire genome. In animals polyploidy is almost always a disaster. In plants it is routine: roughly seven in ten living flowering plant species carry at least one whole-genome duplication somewhere in their ancestry, and ancient duplications underlie all seed plants and all angiosperms. The consequence for tree-building is large: a genome duplication can produce a new species within a single generation, so plant phylogenies cannot be drawn as branches that only ever split and never rejoin.