RT Journal Article SR Electronic T1 Ploidy and the Predictability of Evolution in Fisher’s Geometric Model JF bioRxiv FD Cold Spring Harbor Laboratory SP 001016 DO 10.1101/001016 A1 Sandeep Venkataram A1 Diamantis Sellis A1 Dmitri A. Petrov YR 2013 UL http://biorxiv.org/content/early/2013/12/02/001016.abstract AB Predicting adaptive evolutionary trajectories is a primary goal of evolutionary biology. One can differentiate between forward and backward predictability, where forward predictability measures the likelihood of the same adaptive trajectory occurring in independent evolutions and backward predictability measures the likelihood of a particular adaptive path given the knowledge of starting and final states. Recent studies have attempted to measure both forward and backward predictability using experimental evolution in asexual haploid microorganisms. Similar experiments in diploid organisms have not been conducted. Here we simulate adaptive walks using Fisher’s Geometric Model in haploids and diploids and find that adaptive walks in diploids are less forward- and more backward-predictable than adaptive walks in haploids. We argue that the difference is due to the ability of diploids in our simulations to generate transiently stable polymorphisms and to allow adaptive mutations of larger phenotypic effect. As stable polymorphisms can be generated in both haploid and diploid natural populations through a number of mechanisms, we argue that inferences based on experiments in which adaptive walks proceed through succession of monomorphic states might miss many of the key features of adaptation.