Structure and evolution of opossum, guinea pig, and porcupine cytochrome b genes

Ma Din-Pow, Andrey Zharkikh, Dan Graur, John L. VandeBerg, Wen Hsiung Lie

Research output: Contribution to journalArticlepeer-review

79 Scopus citations


We have sequenced the mitochondrial cytochrome b gene from the guinea pig, the African porcupine, and a South American opossum. A phylogenetic analysis, which includes 22 eutherian and four other vertebrate cytochrome b sequences, indicates that the guinea pig and the porcupine constitute a natural clade (Hystricomorpha) that is not a sister group to the clade of mice and rats (Myomorpha). Therefore, the hypothesis that the Rodentia is paraphyletic receives additional support. The artiodactyls, the perissodactyls, and the cetaceans form a group that is separated from the primates and the rodents. The 26 sequences are used to study the structure/function relationships in cytochrome b, whose function is electron transport. Most of the amino acid residues involved in the two reaction centers are well conserved in evolution. The four histidines that are believed to ligate the two hemes are invariant among the 26 sequences, but their nearby residues are not well conserved in evolution. The eight transmembrane domains represent some of the most divergent regions in the cytochrome b sequence. The rate of nonsynonymous substitution is considerably faster in the human and elephant lineages than in other eutherian lineages; the faster rate might be due to coevolution between cytochrome b and cytochrome c.

Original languageEnglish (US)
Pages (from-to)327-334
Number of pages8
JournalJournal of Molecular Evolution
Issue number4
StatePublished - Apr 1993
Externally publishedYes


  • Cavia porcellus
  • Coevolution
  • Cytochrome b
  • Functional constraints
  • Hystrix africaeaustralis
  • Mammalian phylogeny
  • Mitochondrial DNA
  • Monodelphis domestica

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics


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