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dc.contributor.authorHammond, John Anthony
dc.contributor.authorHauton, Chris
dc.contributor.authorBennett, Kimberley A.
dc.contributor.authorHall, Ailsa Jane
dc.identifier.citationHammond , J A , Hauton , C , Bennett , K A & Hall , A J 2012 , ' Phocid seal leptin : tertiary structure and hydrophobic receptor binding site preservation during distinct leptin gene evolution ' , PLoS ONE , vol. 7 , no. 4 , pp. e35395 .
dc.identifier.otherPURE: 22351694
dc.identifier.otherPURE UUID: 5a531557-5ba9-44eb-b20d-3320356a6c4c
dc.identifier.otherScopus: 84859823930
dc.identifier.otherORCID: /0000-0002-7562-1771/work/47136272
dc.descriptionThis work was supported by funds from the UK Natural Environment Research Councilen
dc.description.abstractThe cytokine hormone leptin is a key signalling molecule in many pathways that control physiological functions. Although leptin demonstrates structural conservation in mammals, there is evidence of positive selection in primates, lagomorphs and chiropterans. We previously reported that the leptin genes of the grey and harbour seals (phocids) have significantly diverged from other mammals. Therefore we further investigated the diversification of leptin in phocids, other marine mammals and terrestrial taxa by sequencing the leptin genes of representative species. Phylogenetic reconstruction revealed that leptin diversification was pronounced within the phocid seals with a high dN/dS ratio of 2.8, indicating positive selection. We found significant evidence of positive selection along the branch leading to the phocids, within the phocid clade, but not over the dataset as a whole. Structural predictions indicate that the individual residues under selection are away from the leptin receptor (LEPR) binding site. Predictions of the surface electrostatic potential indicate that phocid seal leptin is notably different to other mammalian leptins, including the otariids. Cloning the grey seal leptin binding domain of LEPR confirmed that this was structurally conserved. These data, viewed in toto, support a hypothesis that phocid leptin divergence is unlikely to have arisen by random mutation. Based upon these phylogenetic and structural assessments, and considering the comparative physiology and varying life histories among species, we postulate that the unique phocid diving behaviour has produced this selection pressure. The Phocidae includes some of the deepest diving species, yet have the least modified lung structure to cope with pressure and volume changes experienced at depth. Therefore, greater surfactant production is required to facilitate rapid lung re-inflation upon surfacing, while maintaining patent airways. We suggest that this additional surfactant requirement is met by the leptin pulmonary surfactant production pathway which normally appears only to function in the mammalian foetus.
dc.relation.ispartofPLoS ONEen
dc.rights© 2012 Hammond et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.en
dc.subjectQH426 Geneticsen
dc.subjectSDG 14 - Life Below Wateren
dc.titlePhocid seal leptin : tertiary structure and hydrophobic receptor binding site preservation during distinct leptin gene evolutionen
dc.typeJournal articleen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Biologyen
dc.contributor.institutionUniversity of St Andrews. Scottish Oceans Instituteen
dc.contributor.institutionUniversity of St Andrews. Marine Alliance for Science & Technology Scotlanden
dc.contributor.institutionUniversity of St Andrews. Sea Mammal Research Uniten
dc.description.statusPeer revieweden

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