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Full-Text Articles in Life Sciences

The Roles Of Phenotypic Plasticity And Genotypic Specialization In High Altitude Adaptation, Danielle M. Tufts Dec 2013

The Roles Of Phenotypic Plasticity And Genotypic Specialization In High Altitude Adaptation, Danielle M. Tufts

School of Biological Sciences: Dissertations, Theses, and Student Research

In vertebrates living at high altitude, arterial hypoxemia may be ameliorated by reversible changes in the oxygen-carrying capacity of the blood (regulated by erythropoiesis) and/or changes in blood–oxygen affinity (regulated by allosteric effectors of hemoglobin function). These hematological traits often differ between taxa that are native to different elevational zones, but it is often unknown whether the observed physiological differences reflect fixed, genetically based differences or environmentally induced acclimatization responses (phenotypic plasticity). Here, we report measurements of hematological traits related to blood–O2 transport in populations of deer mice (Peromyscus maniculatus) that are native to high- and low-altitude …


Oxygenation Properties And Oxidation Rates Of Mouse Hemoglobins That Differ In Reactive Cysteine Content, Jay F. Storz, Roy E. Weber, Angela Fago Jan 2012

Oxygenation Properties And Oxidation Rates Of Mouse Hemoglobins That Differ In Reactive Cysteine Content, Jay F. Storz, Roy E. Weber, Angela Fago

Jay F. Storz Publications

House mice (genus Mus) harbor extensive allelic variation at two tandemly duplicated genes that encode the β-chain subunits of adult hemoglobin (Hb). Alternative haplotypes differ in the level of sequence divergence between the two β-globin gene duplicates: the Hbbd and Hbbp haplotypes harbor two structurally distinct β-globin genes, whereas the Hbbs haplotype harbors two β-globin duplicates that are identical in sequence. One especially salient difference between the s-type Hbs relative to the d- and p-type Hbs relates to the number of reactive β-chain cysteine residues. In addition to the highly conserved cysteine residue …


Phylogenetic Diversification Of The Globin Gene Superfamily In Chordates, Jay F. Storz, Juan C. Opazo, Federico G. Hoffmann May 2011

Phylogenetic Diversification Of The Globin Gene Superfamily In Chordates, Jay F. Storz, Juan C. Opazo, Federico G. Hoffmann

Jay F. Storz Publications

Phylogenetic reconstructions provide a means of inferring the branching relationships among members of multigene families that have diversified via successive rounds of gene duplication and divergence. Such reconstructions can illuminate the pathways by which particular expression patterns and protein functions evolved. For example, phylogenetic analyses can reveal cases in which similar expression patterns or functional properties evolved independently in different lineages, either through convergence, parallelism, or evolutionary reversals. The purpose of this article is to provide a robust phylogenetic framework for interpreting experimental data and for generating hypotheses about the functional evolution of globin proteins in chordate animals. To do …


Developmental Regulation Of Hemoglobin Synthesis In The Green Anole Lizard Anolis Carolinensis, Jay F. Storz, Federico G. Hoffmann, Juan C. Opazo, Thomas J. Sanger, Hideaki Moriyama Jan 2011

Developmental Regulation Of Hemoglobin Synthesis In The Green Anole Lizard Anolis Carolinensis, Jay F. Storz, Federico G. Hoffmann, Juan C. Opazo, Thomas J. Sanger, Hideaki Moriyama

Jay F. Storz Publications

Tetrapod vertebrates possess multiple alpha- and beta-like globin genes that are ontogenetically regulated, such that functionally distinct hemoglobin (Hb) isoforms are synthesized during different stages of development. The alpha- and beta-like globin genes of amphibians, birds and mammals are differentially expressed during embryonic development and postnatal life, but little is known about the developmental regulation of globin gene expression in non-avian reptiles. Here we report an investigation into the developmental regulation of Hb synthesis in the green anole lizard Anolis carolinensis. We tested two hypotheses derived from comparative genomic studies of the globin gene clusters in tetrapod vertebrates. First, …


Lineage-Specific Patterns Of Functional Diversification In The Α- And Β-Globin Gene Families Of Tetrapod Vertebrates, Federico G. Hoffmann, Jay F. Storz, Thomas A. Gorr, Juan C. Opazo May 2010

Lineage-Specific Patterns Of Functional Diversification In The Α- And Β-Globin Gene Families Of Tetrapod Vertebrates, Federico G. Hoffmann, Jay F. Storz, Thomas A. Gorr, Juan C. Opazo

Jay F. Storz Publications

The α- and β-globin gene families of jawed vertebrates have diversified with respect to both gene function and the developmental timing of gene expression. Phylogenetic reconstructions of globin gene family evolution have provided suggestive evidence that the developmental regulation of hemoglobin synthesis has evolved independently in multiple vertebrate lineages. For example, the embryonic β-like globin genes of birds and placental mammals are not 1:1 orthologs. Despite the similarity in developmental expression profiles, the genes are independently derived from lineage-specific duplications of a β-globin pro-ortholog. This suggests the possibility that other vertebrate taxa may also possess distinct repertoires of globin genes …


Evolution Of Duplicated Β-Globin Genes And The Structural Basis Of Hemoglobin Isoform Differentiation In Mus, Amy M. Runck, Hideaki Moriyama, Jay F. Storz Jan 2009

Evolution Of Duplicated Β-Globin Genes And The Structural Basis Of Hemoglobin Isoform Differentiation In Mus, Amy M. Runck, Hideaki Moriyama, Jay F. Storz

Jay F. Storz Publications

The functional diversification of multigene families may be strongly influenced by mechanisms of concerted evolution such as interparalog gene conversion. The β-globin gene family of house mice (genus Mus) represents an especially promising system for evaluating the effects of gene conversion on the functional divergence of duplicated genes. Whereas the majority of mammalian species possess tandemly duplicated copies of the adult β-globin gene that are identical in sequence, natural populations of house mice are often polymorphic for distinct two-locus haplotypes that differ in levels of functional divergence between duplicated β-globin genes, HBB-T1 and HBB-T2. Here, we use a phylogenetic …


Origin And Ascendancy Of A Chimeric Fusion Gene: The Β/Δ-Globin Gene Of Paenungulate Mammals, Juan C. Opazo, Angela M. Sloan, Kevin L. Campbell, Jay F. Storz Jan 2009

Origin And Ascendancy Of A Chimeric Fusion Gene: The Β/Δ-Globin Gene Of Paenungulate Mammals, Juan C. Opazo, Angela M. Sloan, Kevin L. Campbell, Jay F. Storz

Jay F. Storz Publications

The δ-globin gene (HBD) of eutherian mammals exhibits a propensity for recombinational exchange with the closely linked β-globin gene (HBB) and has been independently converted by the HBB gene in multiple lineages. Here we report the presence of a chimeric β/δ fusion gene in the African elephant (Loxodonta africana) that was created by unequal crossing-over between misaligned HBD and HBB paralogs. The recombinant chromosome that harbors the β/δ fusion gene in elephants is structurally similar to the ‘‘anti-Lepore’’ duplication mutant of humans (the reciprocal exchange product of the hemoglobin Lepore deletion mutant). However, the situation in …


Genomic Evidence For Independent Origins Of Β-Like Globin Genes In Monotremes And Therian Mammals, Juan C. Opazo, Federico G. Hoffmann, Jay F. Storz Feb 2008

Genomic Evidence For Independent Origins Of Β-Like Globin Genes In Monotremes And Therian Mammals, Juan C. Opazo, Federico G. Hoffmann, Jay F. Storz

Jay F. Storz Publications

Phylogenetic reconstructions of the β-globin gene family in vertebrates have revealed that developmentally regulated systems of hemoglobin synthesis have been reinvented multiple times in independent lineages. For example, the functional differentiation of embryonic and adult β-like globin genes occurred independently in birds and mammals. In both taxa, the embryonic β-globin gene is exclusively expressed in primitive erythroid cells derived from the yolk sac. However, the “ε-globin” gene in birds is not orthologous to the ε-globin gene in mammals, because they are independently derived from lineage-specific duplications of a proto β-globin gene. Here, we report evidence that the early and late …


Rapid Rates Of Lineage-Specific Gene Duplication And Deletion In The Α-Globin Gene Family, Federico G. Hoffmann, Juan C. Opazo, Jay F. Storz Jan 2008

Rapid Rates Of Lineage-Specific Gene Duplication And Deletion In The Α-Globin Gene Family, Federico G. Hoffmann, Juan C. Opazo, Jay F. Storz

Jay F. Storz Publications

Phylogeny reconstructions of the globin gene families have revealed that paralogous genes within species are often more similar to one another than they are to their orthologous counterparts in closely related species. This pattern has been previously attributed to mechanisms of concerted evolution such as interparalog gene conversion that homogenize sequence variation between tandemly duplicated genes and therefore create the appearance of recent common ancestry. Here we report a comparative genomic analysis of the α-globin gene family in mammals that reveal a surprisingly high rate of lineage-specific gene duplication and deletion via unequal crossing-over. Results of our analysis reveal that …


The ΑD-Globin Gene Originated Via Duplication Of An Embryonic Α-Like Globin Gene In The Ancestor Of Tetrapod Vertebrates, Federico G. Hoffmann, Jay F. Storz Jun 2007

The ΑD-Globin Gene Originated Via Duplication Of An Embryonic Α-Like Globin Gene In The Ancestor Of Tetrapod Vertebrates, Federico G. Hoffmann, Jay F. Storz

Jay F. Storz Publications

Gene duplication is thought to play an important role in the co-option of existing protein functions to new physiological pathways. The globin superfamily of genes provides an excellent example of the kind of physiological versatility that can be attained through the functional and regulatory divergence of duplicated genes that encode different subunit polypeptides of the tetrameric hemoglobin protein. In contrast to prevailing views about the evolutionary history of the α-globin gene family, here we present phylogenetic evidence that the αA- and αD-globin genes are not the product of a single, tandem duplication of an ancestral globin …


Hemoglobin Function And Physiological Adaptation To Hypoxia In High-Altitude Mammals, Jay F. Storz Feb 2007

Hemoglobin Function And Physiological Adaptation To Hypoxia In High-Altitude Mammals, Jay F. Storz

Jay F. Storz Publications

Understanding the biochemical mechanisms that enable high-altitude animals to survive and function under conditions of hypoxic stress can provide important insights into the nature of physiological adaptation. Evidence from a number of high-altitude vertebrates indicates that modifications of hemoglobin function typically play a key role in mediating an adaptive response to chronic hypoxia. Because much is known about structure– function relationships of mammalian hemoglobins and their physiological role in oxygen transport, the study of hemoglobin variation in high-altitude mammals holds much promise for understanding the nature of adaptation to hypoxia from the level of blood biochemistry to the level of …