The loci of repeated evolution: a catalogue of genetic hotspots of phenotypic variation

What is the nature of the genetic changes underlying phenotypic evolution? We have catalogued 1008 alleles described in the literature that cause phenotypic differences among animals, plants and yeasts. Surprisingly, evolution of similar traits in distinct lineages often involves mutations in the same gene (“gene reuse”). This compilation yields three important qualitative implications about repeated evolution. First, the apparent evolution of similar traits by gene reuse can be traced back to two alternatives, either several independent causative mutations or a single original mutational event followed by sorting processes. Second, hotspots of evolution – defined as the repeated occurrence of de novo mutations at orthologous loci and causing similar phenotypic variation – are omnipresent in the literature with more than 100 examples covering various levels of analysis, including numerous gain-of-function events. Third, several alleles of large effect have been shown to result from the ...