Journal of Molecular Evolution

, Volume 33, Issue 1, pp 34–41

Multigene families and the evolution of complexity

  • Tomoko Ohta

DOI: 10.1007/BF02100193

Cite this article as:
Ohta, T. J Mol Evol (1991) 33: 34. doi:10.1007/BF02100193


Higher organisms are complex, and their developmental processes are controlled by the sequential expression of genes that often form multigene families. Facts are surveyed on how functional diversity of genes is related to duplication of genes or segments of genes, by emphasizing that diversity is often enhanced by alternate splicing and proteolytic cleavage involving duplicated genes or gene segments. Analyses of a population genetics model for the origin of gene families suggest that positive Darwinian selection is needed for acquiring gene families with desirable functions. Based on these considerations, examples that show acceleration of amino acid substitution relative to synonymous change during evolutionary processes are surveyed. Some of such examples strongly suggest that positive selection has worked. In other cases it is difficult to judge whether or not acceleration is caused by positive Darwinian selection. As a general pattern, acceleration of amino acid substitution is often found to be related to gene duplication. It is thought that complexity and diversity of gene function have been advantageous in the long evolutionary course of higher organisms.

Key words

Gene duplicationProgressive evolutionAcceleration of amino acid substitutions

Copyright information

© Springer-Verlag New York Inc. 1991

Authors and Affiliations

  • Tomoko Ohta
    • 1
  1. 1.National Institute of GeneticsMishimaJapan