title: Geographical variation in the rate of evolution: effect of available energy or fluctuating environment?
abstract: In a recent paper, Wright et al. (2003) argue for the hypothesis that greater biologically available energy elevates the rate of molecular evolution. However, their results are also consistent with alternative hypotheses that invoke either environmentally driven variation in effective population sizes, or natural selection, or both. The available energy gradient cited by Wright et al. is linearly correlated with temperature fluctuations, and the observed rate heterogeneity could be a consequence of this environmental variability. The distribution of phylogenetic branch lengths alone is insufficient to distinguish between the hypotheses, and complementary approaches are suggested.
authors.affiliation: Section of Integrative Biology, University of Texas, Austin, Texas 78712, USA. samraat@mail.utexas.edu
authors.forename: Samraat S
authors.initials: SS
authors.lastname: Pawar
mesh_terms: D018744:DNA, Plant / Q000235:genetics*; D004275:DNA, Ribosomal; D004777:Environment; D019143:Evolution, Molecular; D014644:Genetic Variation; D027822:Myrtaceae / Q000235:genetics*; D012641:Selection, Genetic; D012993:Solar Energy; D013696:Temperature
chemical_list: D018744:DNA, Plant; D004275:DNA, Ribosomal