Journal of Molecular Evolution

, Volume 35, Issue 4, pp 292–303

Relative rates of nucleotide substitution at the rbcl locus of monocotyledonous plants


  • Brandon S. Gaut
    • Department of Botany and Plant SciencesUniversity of California
  • Spencer V. Muse
    • Program in Statistical GeneticsNorth Carolina State University
  • W. Dennis Clark
    • Department of BotanyArizona State University
  • Michael T. Clegg
    • Department of Botany and Plant SciencesUniversity of California

DOI: 10.1007/BF00161167

Cite this article as:
Gaut, B.S., Muse, S.V., Clark, W.D. et al. J Mol Evol (1992) 35: 292. doi:10.1007/BF00161167


We subjected 35 rbcL nucleotide sequences from monocotyledonous taxa to maximum likelihood relative rate tests and estimated relative differences in rates of nucleotide substitution between groups of sequences without relying on knowledge of divergence times between taxa. Rate tests revealed that there is a hierarchy of substitution rate at the rbcL locus within the monocots. Among the taxa analyzed the grasses have the most rapid substitution rate; they are followed in rate by the Orchidales, the Liliales, the Bromeliales, and the Arecales. The overall substitution rate for the rbcL locus of grasses is over 5 times the substitution rate in the rbcL of the palms. The substitution rate at the third codon positions in the rbcL of the grasses is over 8 times the third position rate in the palms. The pattern of rate variation is consistent with the generation-time-effect hypothesis. Heterogenous rates of substitution have important implications for phylogenetic reconstruction.

Key words

rbcL Relative rates of nucleotide substitution Generation time Phylogeny construction

Copyright information

© Springer-Verlag New York Inc 1992