Comparative analysis of intra-individual and inter-species DNA sequence variation in salmonid ribosomal DNA cistrons

Kent M. Reed, Jeremiah D. Hackett, Ruth B. Phillips

Research output: Contribution to journalArticle

21 Scopus citations

Abstract

This study examines sequence divergence in three spacer regions of the ribosomal DNA (rDNA) cistron, to test the hypothesis of unequal mutation rates. Portions of two transcribed spacers (ITS-1 and 5' ETS) and the non-transcribed spacer (NTS) or intergenic spacer (IGS) formed the basis of comparative analyses. Sequence divergence was measured both within an individual lake trout (Salvelinus namaycush) and among several related salmonid species (lake trout; brook trout, Salvelinus fontinalis; Arctic char, Salvelinus alpinus; Atlantic salmon, Salmo salar; and brown trout, Salmo trutta). Despite major differences in the length of the rDNA cistron within individual lake trout, minimal sequence difference was detected among cistrons. Interspecies comparisons found that molecular variation in the rDNA spacers did not conform to the predicted pattern of evolution (ITS spacers<ETS spacers<IGS). Specifically, the IGS contains a region that appears to be as highly, or more conserved than the ITS-1.

Original languageEnglish (US)
Pages (from-to)115-125
Number of pages11
JournalGene
Volume249
Issue number1-2
DOIs
StatePublished - May 16 2000
Externally publishedYes

Keywords

  • Intergenic spacer (IGS)
  • Molecular evolution
  • Ribosomal DNA (rDNA)
  • Salmon
  • Trout

ASJC Scopus subject areas

  • Genetics

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