Enhanced evolvability in immunoglobulin V genes under somatic hypermutation.


Journal Article

Darwinian theory requires that mutations be produced in a nonanticipatory manner; it is nonetheless consistent to suggest that mutations that have repeatedly led to nonviable phenotypes would be introduced less frequently than others-if under appropriate genetic control. Immunoglobulins produced during infection acquire point mutations that are subsequently selected for improved binding to the eliciting antigen. We and others have speculated that an enhancement of mutability in the complementarity-determining regions (CDR; where mutations have a greater chance of being advantageous) and/or decrement of mutability in the framework regions (FR; where mutations are more likely to be lethal) may be accomplished by differential codon usage in concert with the known sequence specificity of the hypermutation mechanism. We have examined 115 nonproductively rearranged human Ig sequences. The mutation patterns in these unexpressed genes are unselected and therefore directly reflect inherent mutation biases. Using a chi2 test, we have shown that the number of mutations in the CDRs is significantly higher than the number of mutations found in the FRs, providing direct evidence for the hypothesis that mutations are preferentially targeted into the CDRs.

Full Text

Cited Authors

  • Cowell, LG; Kim, HJ; Humaljoki, T; Berek, C; Kepler, TB

Published Date

  • July 1999

Published In

Volume / Issue

  • 49 / 1

Start / End Page

  • 23 - 26

PubMed ID

  • 10368430

Pubmed Central ID

  • 10368430

International Standard Serial Number (ISSN)

  • 0022-2844

Digital Object Identifier (DOI)

  • 10.1007/pl00006530


  • eng

Conference Location

  • Germany