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dc.contributor.authorZakon, Harold H.  Concept link
dc.contributor.authorJost, Manda C.  Concept link
dc.contributor.authorLu, Ying  Concept link
dc.date.accessioned2010-12-16T19:02:44Z
dc.date.available2011-12-09T09:29:34Z
dc.date.issued2010-11-29
dc.identifier.urihttps://hdl.handle.net/1912/4277
dc.descriptionAuthor Posting. © The Authors, 2010. This is the author's version of the work. It is posted here by permission of Oxford University Press for personal use, not for redistribution. The definitive version was published in Molecular Biology and Evolution 28 (2011): 1415-1424, doi:10.1093/molbev/msq325.en_US
dc.description.abstractMammals have 10 voltage-dependent sodium (Nav) channel genes. Nav channels are expressed in different cell types with different sub-cellular distributions and are critical for many aspects of neuronal processing. The last common ancestor of teleosts and tetrapods had four Nav channel genes presumably on four different chromosomes. In the lineage leading to mammals a series of tandem duplications on two of these chromosomes more than doubled the number of Nav channel genes. It is unknown when these duplications occurred, whether they occurred against a backdrop of duplication of flanking genes on their chromosomes, or as an expansion of ion channel genes in general. We estimated key dates of the Nav channel gene family expansion by phylogenetic analysis using teleost, elasmobranch, lungfish, amphibian, avian, lizard, and mammalian Nav channel sequences, as well as chromosomal synteny for tetrapod genes. We tested, and exclude, the null hypothesis that Nav channel genes reside in regions of chromosomes prone to duplication by demonstrating the lack of duplication or duplicate retention of surrounding genes. We also find no comparable expansion in other voltage dependent ion channel gene families of tetrapods following the teleost-tetrapod divergence. We posit a specific expansion of the Nav channel gene family in the Devonian and Carboniferous periods when tetrapods evolved, diversified, and invaded the terrestrial habitat. During this time the amniote forebrain evolved greater anatomical complexity and novel tactile sensory receptors appeared. The duplication of Nav channel genes allowed for greater regional specialization in Nav channel expression, variation in sub-cellular localization, and enhanced processing of somatosensory input.en_US
dc.description.sponsorshipThis work was funded by the National Science Foundation (IBN 0236147 to H.H.Z and M.C.J), and the National Institutes of Health (R01GM084879 to H.H.Z).en_US
dc.format.mimetypeapplication/pdf
dc.language.isoen_USen_US
dc.relation.urihttps://doi.org/10.1093/molbev/msq325
dc.subjectSodium channelen_US
dc.subjectTetrapodsen_US
dc.subjectAmniotesen_US
dc.subjectTerrestrialityen_US
dc.subjectGene duplicationen_US
dc.subjectBrainen_US
dc.titleExpansion of voltage-dependent Na+ channel gene family in early tetrapods coincided with the emergence of terrestriality and increased brain complexityen_US
dc.typePreprinten_US


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