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Observation of a ZZW female in a natural population: implications for avian sex determination

  • D Arlt
  • Staffan Bensch
  • Bengt Hansson
  • Dennis Hasselquist
  • Helena Westerdahl
Publishing year: 2004
Language: English
Pages: 249-251
Publication/Series: Royal Society of London. Proceedings B. Biological Sciences
Volume: 271
Issue: S4
Document type: Journal article
Publisher: Royal Society

Abstract english

Avian sex determination is chromosomal; however, the underlying mechanisms are not yet understood. There is no conclusive evidence for either of two proposed mechanisms: a dominant genetic switch or a dosage mechanism. No dominant sex-determining gene on the female-specific W chromosome has been found. Birds lack inactivation of one of the Z chromosomes in males, but seem to compensate for a double dose of Z-linked genes by other mechanisms. Recent studies showing female-specific expression of two genes may support an active role of the W chromosome. To resolve the question of avian sex determination the investigation of birds with a 2A: ZZW or 2A: Z0 genotype would be decisive. Here, we report the case of an apparent 2A: ZZW great reed warbler (Acrocephalus arundinaceus) female breeding in a natural population, which was detected using Z-linked microsatellites. Our data strongly suggest a role of W-linked genes in avian sex determination.


  • Biological Sciences


  • Molecular Ecology and Evolution Lab
  • ISSN: 1471-2954
Dennis Hasselquist
E-mail: dennis [dot] hasselquist [at] biol [dot] lu [dot] se



+46 46 222 37 08



Research group


Doctoral students and postdocs

Research fellows


Jacob Roved

PhD Students, main supervisor

PhD Students, assistant supervisor


Interview about my research in the Swedish podcast "Forskarn & jag"