Genome biogeography reveals the intraspecific spread of adaptive mutations for a complex trait

摘要: Physiological novelties are often studied at macro-evolutionary scales such that their micro-evolutionary origins remain poorly understood. Here, we test the hypothesis key components of a complex trait can evolve in isolation and later be combined by gene flow. We use C-4 photosynthesis as study system, derived physiology increases plant productivity warm, dry conditions. The grass Alloteropsis semialata includes non-C-4 genotypes, with some populations using laterally acquired -adaptive loci, providing an outstanding system to track spread novel adaptive mutations. Using genome data from A. individuals spanning species' range, infer date past migrations different parts genome. Our results show photosynthetic types initially diverged isolated populations, where were acquired. However, rare but recurrent subsequent flow allowed loci across genetic pools. Indeed, genes for functions rapidly passed between otherwise distinct genomic backgrounds. Thus, our intraspecific C-4-related variation indicates traits separately through secondary flow, leading assembly optimization evolutionary innovations.