The genetic fate of molecularly cloned simian immunodeficiency virus in experimentally infected macaques

Virology. 1991 Nov;185(1):217-28. doi: 10.1016/0042-6822(91)90769-8.


We have examined genetic variation of the simian immunodeficiency virus (SIV) in four macaques inoculated with virions derived from molecular clones of proviral DNA. Our data demonstrated that the SIV genome is capable of rapid and extensive genetic variation. This variation was especially large in the env gene, where nucleotide substitution frequencies were as high as 10(-1)/site/year. In some env clones, a high G to A transition rate was observed that accounted for up to 79% of the observed nucleotide substitutions. Moreover, in env clones with a high G to A transition rate, multiple in-frame stop codons were generated exclusively at tryptophan codons. Another interesting observation was the lack of variation in the region analogous to the V3 loop in the HIV-1 Env protein. Considered together, these data have important implications for studies of pathogenesis and vaccine development in the SIV model system.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cells, Cultured
  • Cloning, Molecular
  • Codon / genetics
  • DNA Nucleotidyltransferases / genetics
  • DNA, Viral / genetics*
  • DNA, Viral / isolation & purification
  • Genes, env*
  • Genetic Variation*
  • HIV-2 / genetics
  • Integrases
  • Macaca mulatta
  • Molecular Sequence Data
  • Polymerase Chain Reaction / methods
  • Proviruses / genetics
  • Restriction Mapping
  • Sequence Homology, Nucleic Acid
  • Simian Acquired Immunodeficiency Syndrome / microbiology*
  • Simian Immunodeficiency Virus / genetics*


  • Codon
  • DNA, Viral
  • DNA Nucleotidyltransferases
  • Integrases