Journal of Heredity Advance Access originally published online on April 14, 2009
Journal of Heredity 2009 100(Supplement 1):S90-S100; doi:10.1093/jhered/esp015
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This article appears in the following Journal of Heredity issue: Symposium Issue: Fourth International Conference on Advances in Canine and Feline Genomics and Inherited Diseases, Saint Malo, Brittany, France, 21-24 May 2008. [View the issue table of contents]
Original Articles |
Analyses of Sweet Receptor Gene (Tas1r2) and Preference for Sweet Stimuli in Species of Carnivora
From the Monell Chemical Senses Center, Philadelphia, PA 19104 (Xia Li, Weihua Li, Beauchamp, and Brand); the Anthropological Institute and Museum, University of Zurich, Zurich, Switzerland (Glaser); the Laboratory of Genomic Diversity, National Cancer Institute, Frederick, MD (Johnson and O'Brien); the Department of Psychology, School of Arts and Sciences, University of Pennsylvania, Philadelphia, PA (Beauchamp); Department of Anatomy, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA (Beauchamp); the Department of Biochemistry, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA (Brand)
Address correspondence to Xia Li or Joesph Brand at the address above, or e-mail: xiali{at}monell.org; brand{at}monell.org.
The extent to which taste receptor specificity correlates with, or even predicts, diet choice is not known. We recently reported that the insensitivity to sweeteners shown by species of Felidae can be explained by their lacking of a functional Tas1r2 gene. To broaden our understanding of the relationship between the structure of the sweet receptors and preference for sugars and artificial sweeteners, we measured responses to 12 sweeteners in 6 species of Carnivora and sequenced the coding regions of Tas1r2 in these same or closely related species. The lion showed no preference for any of the 12 sweet compounds tested, and it possesses the pseudogenized Tas1r2. All other species preferred some of the natural sugars, and their Tas1r2 sequences, having complete open reading frames, predict functional sweet receptors. In addition to preferring natural sugars, the lesser panda also preferred 3 (neotame, sucralose, and aspartame) of the 6 artificial sweeteners. Heretofore, it had been reported that among vertebrates, only Old World simians could taste aspartame. The observation that the lesser panda highly preferred aspartame could be an example of evolutionary convergence in the identification of sweet stimuli.
Key Words: carnivore • diet • sweeteners • sweet receptor • taste testing
Corresponding Editor: William Murphy
Received November 21, 2008
Revised February 12, 2009
Accepted February 26, 2009