Journal of Heredity Advance Access published online on June 20, 2008
Journal of Heredity, doi:10.1093/jhered/esn051
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Detection of Olfactory Receptor Transcripts in Bird Testes
From the Max-Planck Institute for Ornithology, Department of Behavioural Ecology & Evolutionary Genetics, PO Box 1564, 82319 Starnberg, Germany (Steiger and Kempenaers); and the Cawthron Institute, Private Bag 2, Nelson, New Zealand (Fidler)
Address correspondence to Silke S. Steiger at the address above, or e-mail: steiger{at}orn.mpg.de.
The sense of smell is mediated through olfactory receptors (ORs) expressed in olfactory sensory neurons of the olfactory epithelium. Interestingly, some OR genes also function in another context: they are expressed in nonolfactory testicular tissue and in sperm of mammals and fish where they mediate sperm flagellar motility. The presence of OR transcripts in testicular tissue of both mammals and fish suggests that this is a conserved trait among vertebrates. In birds, sperm competition is widespread and its outcome depends, in part, on sperm motility. Thus, avian testicular OR gene expression might be particularly interesting to study, especially in the context of current ideas on postcopulatory sexual selection. Using reverse transcription–polymerase chain reaction with degenerate primers specific for OR genes and subsequent cloning, we here demonstrate that multiple OR gene transcripts are present in chicken (Gallus gallus domesticus) testes. Moreover, we show that they belong to the class-
OR gene clade. We discuss the potential significance and evolutionary implications of avian testicular OR gene expression.
Corresponding Editor: Jerry Dodgson
Received December 12, 2007
Accepted April 22, 2008