Mutation rates are proposed to be a pragmatic balance struck between the harmful effects of mutations and the costs of suppressing them; this hypothesis predicts that longer-lived body parts and those that contribute to the next generation should have lower mutation rates than the rest of the organism, but is this the case in nature? New research publishing April 9 in the open-access journal PLOS Biology from Long Wang, Dacheng Tian, Sihai Yang and colleagues from Nanjing University, China along with Laurence Hurst from the Milner Centre for Evolution at the University of Bath, UK, now provide the first test of the generality of these ideas by looking in plants.