Journal of Molecular Evolution

, Volume 64, Issue 2, pp 158–170

Molecular Population Genetics of the α-Esterase5 Gene Locus in Original and Colonized Populations of Drosophila buzzatii and Its Sibling Drosophila koepferae

  • R. V. Piccinali
  • L. J. Mascord
  • J. S. F. Barker
  • J. G. Oakeshott
  • E. Hasson
Article

DOI: 10.1007/s00239-005-0224-y

Cite this article as:
Piccinali, R.V., Mascord, L.J., Barker, J.S.F. et al. J Mol Evol (2007) 64: 158. doi:10.1007/s00239-005-0224-y

Abstract

Several studies have suggested that esterase-2 (EST-2) may be the target of natural selection in the cactophilic fly Drosophila buzzatii. In this work, we analyzed nucleotide variation in a fragment of α-esterase5E5), the gene encoding EST-2, in original (Argentinian) and colonized (Australian) populations of D. buzzatii and in its sibling D. koepferae. Estimates of nucleotide heterozygosity in D. buzzatii were similar in Australia and Argentina, although we detected a loss of singletons in colonized populations, suggesting a moderate founder effect. Interspecific comparisons revealed that D. buzzatii was more polymorphic for nonsynonymous variation, whereas D. koepferae was more variable for synonymous and noncoding sites. The two major chromosomal arrangements (2st and 2j) in D. buzzatii displayed similar levels of nucleotide variation, whereas 2jz3 was monomorphic. The sequenced region allowed the discrimination of a greater number of EST-2 protein variants in the Australian sample than in the Argentinean sample. In D. koepferae, nucleotide variation in αE5 does not depart from neutral expectations, although tests of population structure were significant for silent variation. In contrast, D. buzzatii has probably undergone a recent population expansion in its South American range. In addition, the McDonald and Kreitman test revealed an excess of nonsynonymous polymorphism in both original and colonized populations of this species.

Keywords

αE5Cactophilic DrosophilaExcess of nonsynonymous polymorphismFounder effectPopulation expansion

Supplementary material

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Supplementary material

Copyright information

© Springer Science+Business Media, Inc. 2006

Authors and Affiliations

  • R. V. Piccinali
    • 1
  • L. J. Mascord
    • 2
  • J. S. F. Barker
    • 2
  • J. G. Oakeshott
    • 3
  • E. Hasson
    • 1
  1. 1.Departamento de Ecología, Genética y Evolución, Facultad de Ciencias Exactas y NaturalesUniversidad de Buenos AiresBuenos AiresArgentina
  2. 2.School of Rural Science and Agriculture, Faculty of the SciencesUniversity of New EnglandArmidaleAustralia
  3. 3.Division of EntomologyCommonwealth Scientific and Industrial Research OrganisationCanberraAustralia