Document Detail

Historical reconstructions of evolving physiological complexity: O2 secretion in the eye and swimbladder of fishes.
MedLine Citation:
PMID:  17449830     Owner:  NLM     Status:  MEDLINE    
The ability of some fishes to inflate their compressible swimbladder with almost pure oxygen to maintain neutral buoyancy, even against the high hydrostatic pressure several thousand metres below the water surface, has fascinated physiologists for more than 200 years. This review shows how evolutionary reconstruction of the components of such a complex physiological system on a phylogenetic tree can generate new and important insights into the origin of complex phenotypes that are difficult to obtain with a purely mechanistic approach alone. Thus, it is shown that oxygen secretion first evolved in the eyes of fishes, presumably for improved oxygen supply to an avascular, metabolically active retina. Evolution of this system was facilitated by prior changes in the pH dependence of oxygen-binding characteristics of haemoglobin (the Root effect) and in the specific buffer value of haemoglobin. These changes predisposed teleost fishes for the later evolution of swimbladder oxygen secretion, which occurred at least four times independently and can be associated with increased auditory sensitivity and invasion of the deep sea in some groups. It is proposed that the increasing availability of molecular phylogenetic trees for evolutionary reconstructions may be as important for understanding physiological diversity in the postgenomic era as the increase of genomic sequence information in single model species.
Michael Berenbrink
Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  The Journal of experimental biology     Volume:  210     ISSN:  0022-0949     ISO Abbreviation:  J. Exp. Biol.     Publication Date:  2007 May 
Date Detail:
Created Date:  2007-04-23     Completed Date:  2008-01-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0243705     Medline TA:  J Exp Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1641-52     Citation Subset:  IM    
School of Biological Sciences, The University of Liverpool, Biosciences Building, Crown Street, Liverpool, UK.
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MeSH Terms
Air Sacs / blood supply,  physiology*
Evolution, Molecular
Eye / blood supply,  secretion*
Fishes / genetics,  physiology*
Hemoglobins / genetics,  metabolism
Hydrogen-Ion Concentration
Oxygen / metabolism*
Systems Biology / methods
Reg. No./Substance:
0/Hemoglobins; 7782-44-7/Oxygen

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