Please use this identifier to cite or link to this item: http://hdl.handle.net/2440/51857
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Type: Journal article
Title: Loss of genes implicated in gastric function during platypus evolution
Author: Ordonez, G.
Hillier, L.
Warren, W.
Grutzner, F.
Lopez-Otin, C.
Puente, X.
Citation: Genome Biology (Online Edition), 2008; 9(5):R81-1-R81-11
Publisher: BioMed Central Ltd.
Issue Date: 2008
ISSN: 1474-760X
1474-760X
Statement of
Responsibility: 
Gonzalo R Ordoñez, LaDeana W Hillier, Wesley C Warren, Frank Grützner, Carlos López-Otín and Xose S Puente
Abstract: Background The duck-billed platypus (Ornithorhynchus anatinus) belongs to the mammalian subclass Prototheria, which diverged from the Theria line early in mammalian evolution. The platypus genome sequence provides a unique opportunity to illuminate some aspects of the biology and evolution of these animals. Results We show that several genes implicated in food digestion in the stomach have been deleted or inactivated in platypus. Comparison with other vertebrate genomes revealed that the main genes implicated in the formation and activity of gastric juice have been lost in platypus. These include the aspartyl proteases pepsinogen A and pepsinogens B/C, the hydrochloric acid secretion stimulatory hormone gastrin, and the α subunit of the gastric H+/K+-ATPase. Other genes implicated in gastric functions, such as the β subunit of the H+/K+-ATPase and the aspartyl protease cathepsin E, have been inactivated because of the acquisition of loss-of-function mutations. All of these genes are highly conserved in vertebrates, reflecting a unique pattern of evolution in the platypus genome not previously seen in other mammalian genomes. Conclusion The observed loss of genes involved in gastric functions might be responsible for the anatomical and physiological differences in gastrointestinal tract between monotremes and other vertebrates, including small size, lack of glands, and high pH of the monotreme stomach. This study contributes to a better understanding of the mechanisms that underlie the evolution of the platypus genome, might extend the less-is-more evolutionary model to monotremes, and provides novel insights into the importance of gene loss events during mammalian evolution.
Keywords: Stomach; Gastric Acid; Animals; Platypus; Pepsin A; Evolution, Molecular; Gene Silencing; Gene Deletion; Digestion; Biological Evolution
Rights: © 2008 Ordoñez et al.; licensee BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
RMID: 0020081545
DOI: 10.1186/gb-2008-9-5-r81
Appears in Collections:Molecular and Biomedical Science publications
Environment Institute Leaders publications

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