Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature
Notothenioids represent a large group of marine teleosts that are mostly endemic to the Antarctic Ocean. In this environment, the low metabolic demand and the high oxygen concentration reduce the need for hemoglobin(s) [Hb(s)]. The extreme condition is represented by the icefish (Channichthyidae, No...
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ftpubmed:oai:pubmedcentral.nih.gov:21134 2023-05-15T14:04:40+02:00 Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature Bargelloni, Luca Marcato, Stefania Patarnello, Tomaso 1998-07-21 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC21134 http://www.ncbi.nlm.nih.gov/pubmed/9671736 en eng The National Academy of Sciences http://www.ncbi.nlm.nih.gov/pmc/articles/PMC21134 http://www.ncbi.nlm.nih.gov/pubmed/9671736 Copyright © 1998, The National Academy of Sciences Biological Sciences Text 1998 ftpubmed 2013-08-29T07:00:52Z Notothenioids represent a large group of marine teleosts that are mostly endemic to the Antarctic Ocean. In this environment, the low metabolic demand and the high oxygen concentration reduce the need for hemoglobin(s) [Hb(s)]. The extreme condition is represented by the icefish (Channichthyidae, Notothenioidei), the only vertebrates that lack Hb. We obtained the nucleotide sequence coding for the β-globin chain of the single major Hb form in six red-blooded notothenioids. These included Gymnodraco acuticeps, one of the closest species to the Hb-less icefish, which is also the only known fish having a single Hb without Bohr effect. This species shows a higher rate of nonsynonymous substitutions (KA), in contrast with the homogeneity of synonymous substitution (KS) rates, and KA/KS ratios significantly greater than one in the majority of comparisons. These results are suggestive of positive selection, diversifying the single major Hb toward specialized functions. A single Hb that is free to diversify means that its role in routine oxygen transport can be reduced in the presence of a combination of physiological, ecological, and environmental factors. Although a reduced “routine” function for Hb, as is apparent in G. acuticeps, might, indeed, evoke the lack of Hb in icefish, evidence of diversifying selection reported here is at variance with the hypothesis of a simple trend from a single Hb toward the Hb-less condition. Text Antarc* Antarctic Antarctic Ocean Icefish PubMed Central (PMC) Antarctic Antarctic Ocean The Antarctic |
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Biological Sciences Bargelloni, Luca Marcato, Stefania Patarnello, Tomaso Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature |
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Biological Sciences |
description |
Notothenioids represent a large group of marine teleosts that are mostly endemic to the Antarctic Ocean. In this environment, the low metabolic demand and the high oxygen concentration reduce the need for hemoglobin(s) [Hb(s)]. The extreme condition is represented by the icefish (Channichthyidae, Notothenioidei), the only vertebrates that lack Hb. We obtained the nucleotide sequence coding for the β-globin chain of the single major Hb form in six red-blooded notothenioids. These included Gymnodraco acuticeps, one of the closest species to the Hb-less icefish, which is also the only known fish having a single Hb without Bohr effect. This species shows a higher rate of nonsynonymous substitutions (KA), in contrast with the homogeneity of synonymous substitution (KS) rates, and KA/KS ratios significantly greater than one in the majority of comparisons. These results are suggestive of positive selection, diversifying the single major Hb toward specialized functions. A single Hb that is free to diversify means that its role in routine oxygen transport can be reduced in the presence of a combination of physiological, ecological, and environmental factors. Although a reduced “routine” function for Hb, as is apparent in G. acuticeps, might, indeed, evoke the lack of Hb in icefish, evidence of diversifying selection reported here is at variance with the hypothesis of a simple trend from a single Hb toward the Hb-less condition. |
format |
Text |
author |
Bargelloni, Luca Marcato, Stefania Patarnello, Tomaso |
author_facet |
Bargelloni, Luca Marcato, Stefania Patarnello, Tomaso |
author_sort |
Bargelloni, Luca |
title |
Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature |
title_short |
Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature |
title_full |
Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature |
title_fullStr |
Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature |
title_full_unstemmed |
Antarctic fish hemoglobins: Evidence for adaptive evolution at subzero temperature |
title_sort |
antarctic fish hemoglobins: evidence for adaptive evolution at subzero temperature |
publisher |
The National Academy of Sciences |
publishDate |
1998 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC21134 http://www.ncbi.nlm.nih.gov/pubmed/9671736 |
geographic |
Antarctic Antarctic Ocean The Antarctic |
geographic_facet |
Antarctic Antarctic Ocean The Antarctic |
genre |
Antarc* Antarctic Antarctic Ocean Icefish |
genre_facet |
Antarc* Antarctic Antarctic Ocean Icefish |
op_relation |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC21134 http://www.ncbi.nlm.nih.gov/pubmed/9671736 |
op_rights |
Copyright © 1998, The National Academy of Sciences |
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