Isoenzyme status and genetic variability of serum esterases in the lesser snow goose, Anser caerulescens caerulescens

Thaddeus A. Bargiello, Joseph Grossfield, R. W. Steele, Fred Cooke

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9 Scopus citations


A maximum of 22 bands comprising four esterase subgroups-acetylesterase, carboxylesterase, cholinesterase, and acetylcholinesterase-were detected following electrophoresis of lesser snow goose sera on polyacrylamide gels. A minimum of seven structural genes was surmised to be involved in the biosynthesis of these enzymes following physiochemical characterizations. The genetic variability of these loci was calculated to be 1.25% average heterozygosity, while 14.3% of the loci were polymorphic. These estimates of genetic variability were substantially lower than those reported for other vertebrate species. The low degree of genetic variability found in snow goose serum esterases coupled with the extensive protein multiplicity observed may possibly reflect an adaptive strategy based on "biochemical plasticity" rather than genic heterozygosity for this species. The nature of evolutionary forces acting upon multiple enzyme systems such as esterases is discussed. The concept of "conditional neutrality" is introduced and defined within this context.

Original languageEnglish (US)
Pages (from-to)741-763
Number of pages23
JournalBiochemical Genetics
Issue number7-8
Publication statusPublished - Aug 1977



  • electrophoretic genetic variability
  • esterases
  • isoenzyme status
  • snow goose

ASJC Scopus subject areas

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

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