Skip Navigation



MBE Advance Access published online on February 16, 2006
Molecular Biology and Evolution, doi:10.1093/molbev/msj106
This Article
Right arrow Advance Access manuscript (PDF) Freely available
Right arrow Supplementary Material
Right arrow All Versions of this Article:
23/5/964    most recent
msj106v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Go, Y.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Go, Y.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2006. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oxfordjournals.org
Accepted January 30, 2006

Research Article

Lineage-Specific Expansions and Contractions of the Bitter Taste Receptor Gene Repertoire in Vertebrates

Yasuhiro Go 1 *

1 Department of Biosystems Science, The Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa 240-0193, Japan

* To whom correspondence should be addressed.
Yasuhiro Go, E-mail: go_yasuhiro{at}soken.ac.jp


  Abstract

The sense of bitter taste plays a critical role in how organisms avoid generally bitter toxic and harmful substances. Previous studies revealed that there were 25 intact bitter taste receptor (T2R) genes in humans and 34 in mice. However, since the recent chicken genome project reported only three T2R genes, it appears that extensive gene expansions occurred in the lineage leading to mammals or extensive gene contractions occurred in the lineage leading to birds. Here, I examined the T2R gene repertoire in placental mammals (dogs, Canis familiaris; and cows, Bos taurus), marsupials (opossums, Monodelphis domestica), amphibians (frogs, Xenopus tropicalis), and fishes (zebrafishes, Danio rerio; and pufferfishes, Takifugu rubripes) to investigate the birth-and-death process of T2R genes throughout vertebrate evolution. I show that (1) the first extensive gene expansions occurred before the divergence of mammals from reptiles/birds but after the divergence of amniotes (reptiles/birds/mammals) from amphibians, (2) subsequent gene expansions continuously took place in the ancestral mammalian lineage and the lineage leading to amphibians, as evidenced by the presence of 15, 18, 26, and 49 intact T2R genes in the dog, cow, opossum, and frog genome, respectively, and (3) contractions of the gene repertoire happened in the lineage leading to chickens. Thus, continuous gene expansions have shaped the T2R repertoire in mammals, but the contractions subsequent to the first round of expansions have made the chicken T2R repertoire narrow. These dramatic changes in the repertoire size might reflect the daily intake of foods from an external environment as a driving force of evolution.

Keywords: bitter taste receptor genes; gene expansion; gene contraction; sensory genes; mammal; chicken.
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 J HeredHome page
X. Li, D. Glaser, W. Li, W. E. Johnson, S. J. O'Brien, G. K. Beauchamp, and J. G. Brand
Analyses of Sweet Receptor Gene (Tas1r2) and Preference for Sweet Stimuli in Species of Carnivora
J. Hered., July 1, 2009; 100(suppl_1): S90 - S100.
[Abstract] [Full Text] [PDF]

Home page
 J. Neurosci.Home page
H. Oike, T. Nagai, A. Furuyama, S. Okada, Y. Aihara, Y. Ishimaru, T. Marui, I. Matsumoto, T. Misaka, and K. Abe
Characterization of Ligands for Fish Taste Receptors
J. Neurosci., May 23, 2007; 27(21): 5584 - 5592.
[Abstract] [Full Text] [PDF]


Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.