Teleost introns are characterized by a high A+T content

Paul Winnard, Bruce D. Sidell, Michael E. Vayda

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


We previously observed that Antarctic fish genes contain intron sequences of high A+T content (60-70% average A+T) which are in stark contrast with adjacent protein coding-sequences. Here, we report that this disparity in intron/exon base composition is a common feature among teleosts. We analyzed 483 teleost genomic DNA sequences, containing 2583 introns, from 80 teleost genera that populate polar, temperate, or tropical habitats. Eighty-nine percent of teleost introns display an A+T content between 50-84% A+T with a mean of 60% A+T. In contrast, only 37% of teleost exons have an A+T content greater-than 50% with a mean of 48% A+T. A comparison to homologous mammalian genes showed a striking difference; in this case, introns and exons have similar base compositions, averaging 45-47% A+T. This indicates that most teleost genes exhibit a large difference in base composition between their introns and exons. There was no correlation of teleost intron A+T content to intron length or habitat temperature range. Thus, teleost intron sequences tend to show the common feature of being much higher in A+T content then neighboring exons.

Original languageEnglish (US)
Pages (from-to)155-161
Number of pages7
JournalComparative Biochemistry and Physiology - B Biochemistry and Molecular Biology
Issue number2
StatePublished - Oct 1 2002
Externally publishedYes


  • A+T content
  • Antarctic icefish
  • Base composition
  • Body temperature
  • Exons
  • Introns
  • Teleost

ASJC Scopus subject areas

  • Biochemistry
  • Physiology
  • Molecular Biology


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