Journal of Molecular Evolution

, Volume 32, Issue 2, pp 187–198

cDNA and amino acid sequences of rainbow trout (Oncorhynchus mykiss) lysozymes and their implications for the evolution of lysozyme and lactalbumin


  • André Dautigny
    • Laboratory of ProteinsUniversity of Paris V
  • Ellen M. Prager
    • Division of Biochemistry and Molecular BiologyUniversity of California
  • Danièle Pham-Dinh
    • Laboratory of ProteinsUniversity of Paris V
  • Jacqueline Jollès
    • Laboratory of ProteinsUniversity of Paris V
  • Farzad Pakdel
    • Molecular Biology LaboratoryUniversity of Rennes I
  • Bjørn Grinde
    • National Institute of Public Health
  • Pierre Jollès
    • Laboratory of ProteinsUniversity of Paris V

DOI: 10.1007/BF02515392

Cite this article as:
Dautigny, A., Prager, E.M., Pham-Dinh, D. et al. J Mol Evol (1991) 32: 187. doi:10.1007/BF02515392


The complete 129-amino-acid sequences of two rainbow trout lysozymes (I and II) isolated from kidney were established using protein chemistry microtechniques. The two sequences differ only at position 86, I having aspartic acid and II having alanine. A cDNA clone coding for rainbow trout lysozyme was isolated from a cDNA library made from liver mRNA. Sequencing of the cloned cDNA insert, which was 1 kb in length, revealed a 432-bp open reading frame encoding an amino-terminal peptide of 15 amino acids and a mature enzyme of 129 amino acids identical in sequence to II. Forms I and II from kidney and liver were also analyzed using enzymatic amplification via PCR and direct sequencing; both organs contain mRNA encoding the two lysozymes. Evolutionary trees relating DNA sequences coding for lysozymesc and α-lactalbumins provide evidence that the gene duplication giving rise to conventional vertebrate lysozymesc and to lactalbumin preceded the divergence of fishes and tetrapods about 400 Myr ago. Evolutionary analysis also suggests that amino acid replacements may have accumulated more slowly on the lineage leading to fish lysozyme than on those leading to mammal and bird lysozymes.

Key words

Conventional lysozymesCalciumbinding lysozymesGene duplicationsTetrapodsInsectsEvolutionary treesStatistical testingReplacement mutationsBase compositionPCR



complementary DNA


million years


150 mM sodium chloride, 15 mM sodium citrate pH 7.0


polymerase chain reaction

Copyright information

© Springer-Verlag York Inc 1991