UC Davis

Convergent evolution has fascinated and occasionally mystified biologists since the principle of universal common ancestry was accepted. Similar phenotypes can arise by common ancestry (including preadaptations) or through constraints in the space of possible phenotypes and can increase in a population via either drift or selection. Assessing which of these mechanisms to invoke for any given example remains challenging for both simple and complex phenotypes. However, barriers in this area are slowly breaking down with recent advances in genomics and systems biology. Arenaissance in the study of convergent evolution may be on its way, as surprising explanations for similar phenotypes, such as the metabolic similarities between yeast and cancer cells, are uncovered with network and metabolic models. We argue that although examples of convergence are known from many domains of life, green plants in particular have remarkable promise for the study of convergence because they are experimentally tractable, have considerable “-omics” and systems biology resources available, and show convergence in a number of important and complex traits. Four such examples include the domestication syndrome, duplicate loss and retention patterns following whole-genome duplication, the multiple appearances of C4 and crassulacean acid metabolism photosynthesis, and hybrid vigor.