Codon-Substitution Models for Detecting Molecular Adaptation at Individual Sites Along Specific Lineages

The nonsynonymous (amino acid-altering) to synonymous (silent) substitution rate ratio (omega = d(N)/d(S)) provides a measure of natural selection at the protein level, with omega = 1, >1, and

• NS
  National Science Foundation
• BA
  Biotechnology and Biological Sciences Research Council