Evolution of cytochromec investigated by the maximum parsimony method

Summary Rates of evolution for cytochromec over the past one billion years were calculated from a maximum parsimony dendrogram which approximates the phylogeny of 87 lineages. Two periods of evolutionary acceleration and deceleration apparently occurred for the cytochromec molecule. The tempo of evolutionary change indicated by this analysis was compared to the patterns of acceleration and deceleration in the ancestry of several other proteins The synchrony of these tempos of molecular change supports the notion that rapid genetic evolution accompanied periods of major adaptive radiations.Rates of change at different times in several structural-functional areas of cytochromec were also investigated in order to test the Darwinian hypothesis that during periods of rapid evolution, functional sites accumulate proportionately more substitutions than areas with no known function. Rates of change in four proposed functional groupings of sites were therefore compared to rates in areas of unknown function for several different time periods. This analysis revealed a significant increase in the rate of evolution for sites associated with the regions of cytochromec oxidase and reductase interaction during the period between the emergence of the eutherian ancestor to the emergence of the anthropoid ancestor.