Journal of Molecular Evolution

, Volume 15, Issue 2, pp 113–127

Origins of immunoglobulin heavy chain domains

  • Winona C. Barker
  • Lynne K. Ketcham
  • Margaret O. Dayhoff
Article

DOI: 10.1007/BF01732665

Cite this article as:
Barker, W.C., Ketcham, L.K. & Dayhoff, M.O. J Mol Evol (1980) 15: 113. doi:10.1007/BF01732665

Summary

Using computer programs that analyze the evolutionary history and probability of relationship of protein sequences, we have investigated the gene duplication events that led to the present configuration of immunoglobulin C regions, with particular attention to the origins of the homology regions (domains) of the heavy chains. We conclude that all of the sequenced heavy chains share a common ancestor consisting of four domains and that the two shorter heavy chains, alpha and gamma, have independently lost most of the second domain. These conclusions allow us to align corresponding regions of these sequences for the purpose of deriving evolutionary trees. Three independent internal gene duplications are postulated to explain the observed pattern of relationships among the four domains: first a duplication of the ancestral single domain C region, followed by independent duplications of the resulting first and last domains. In these studies there was no evidence of crossing-over and recombination between ancestral chains of different classes; however, certain types of recombinations would not be detectable from the available sequence data.

Key words

Immunoglobulin C regions Evolutionary trees Internal gene duplications Heavy chain domains Computer methods 

Copyright information

© Springer-Verlag 1980

Authors and Affiliations

  • Winona C. Barker
    • 1
  • Lynne K. Ketcham
    • 1
  • Margaret O. Dayhoff
    • 1
  1. 1.National Biomedical Research FoundationGeorgetown University Medical CenterWashington, D.C.USA