Mechanistic model of evolutionary rate variation en route to a nonphotosynthetic lifestyle in plants.

ABSTRACT: Because novel environmental conditions alter the selection pressure on genes or entire subgenomes, adaptive and nonadaptive changes will leave a measurable signature in the genomes, shaping their molecular evolution. We present herein a model of the trajectory of plastid genome evolution under progressively relaxed functional constraints during the transition from autotrophy to a nonphotosynthetic parasitic lifestyle. We show that relaxed purifying selection in all plastid genes is linked to obligate parasitism, characterized by the parasite's dependence on a host to fulfill its life cycle, rather than the loss of photosynthesis. Evolutionary rates and selection pressure coevolve with macrostructural and microstructural changes, the extent of functional reduction, and the establishment of

SUBMITTER: Wicke S 

PROVIDER: S-EPMC4987836 | biostudies-literature | 2016 Aug

REPOSITORIES: biostudies-literature