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Energy Demand And The Context-Dependent Effects Of Genetic Interactions Underlying Metabolism, Luke A. Hoekstra, Cole R. Julick, Katelyn M. Mika, Kristi L. Montooth
Energy Demand And The Context-Dependent Effects Of Genetic Interactions Underlying Metabolism, Luke A. Hoekstra, Cole R. Julick, Katelyn M. Mika, Kristi L. Montooth
School of Biological Sciences: Faculty Publications
Genetic effects are often context dependent, with the same genotype differentially affecting phenotypes across environments, life stages, and sexes.We used an environmental manipulation designed to increase energy demand during development to investigate energy demand as a general physiological explanation for context-dependent effects of mutations, particularly for those mutations that affect metabolism. We found that increasing the photoperiod during which Drosophila larvae are active during development phenocopies a temperature-dependent developmental delay in a mitochondrial-nuclear genotype with disrupted metabolism. This result indicates that the context-dependent fitness effects of this genotype are not specific to the effects of temperature and may generally result …
Epistasis Constrains Mutational Pathways Of Hemoglobin Adaptation In High-Altitude Pikas, Danielle M. Tufts, Chandrasekhar Natarajan, Inge G. Revsbech, Joana Projecto- Garcia, Federico G. Hoffmann, Roy E. Weber, Angela Fago, Hideaki Moriyama, Jay F. Storz
Epistasis Constrains Mutational Pathways Of Hemoglobin Adaptation In High-Altitude Pikas, Danielle M. Tufts, Chandrasekhar Natarajan, Inge G. Revsbech, Joana Projecto- Garcia, Federico G. Hoffmann, Roy E. Weber, Angela Fago, Hideaki Moriyama, Jay F. Storz
School of Biological Sciences: Faculty Publications
A fundamental question in evolutionary genetics concerns the roles of mutational pleiotropy and epistasis in shaping trajectories of protein evolution. This question can be addressed most directly by using site-directed mutagenesis to explore the mutational landscape of protein function in experimentally defined regions of sequence space. Here, we evaluate how pleiotropic trade-offs and epistatic interactions influence the accessibility of alternative mutational pathways during the adaptive evolution of hemoglobin (Hb) function in high-altitude pikas (Mammalia: Lagomorpha). By combining ancestral protein resurrection with a combinatorial protein-engineering approach, we examined the functional effects of sequential mutational steps in all possible pathways that produced …
Repeated Elevational Transitions In Hemoglobin Function During The Evolution Of Andean Hummingbirds, Joana Projecto-Garcia, Chandrasekhar Natarajan, Hideaki Moriyama, Roy E. Weber, Angela Fago, Zachary A. Cheviron, Robert Dudley, Jimmy A. Mcguire, Christopher C. Witt, Jay F. Storz
Repeated Elevational Transitions In Hemoglobin Function During The Evolution Of Andean Hummingbirds, Joana Projecto-Garcia, Chandrasekhar Natarajan, Hideaki Moriyama, Roy E. Weber, Angela Fago, Zachary A. Cheviron, Robert Dudley, Jimmy A. Mcguire, Christopher C. Witt, Jay F. Storz
School of Biological Sciences: Faculty Publications
Animals that sustain high levels of aerobic activity under hypoxic conditions (e.g., birds that fly at high altitude) face the physiological challenge of jointly optimizing blood-O2 affinity for O2 loading in the pulmonary circulation and O2 unloading in the systemic circulation. At high altitude, this challenge is especially acute for small endotherms like hummingbirds that have exceedingly high mass-specific metabolic rates. Here we report an experimental analysis of hemoglobin (Hb) function in South American hummingbirds that revealed a positive correlation between Hb-O2 affinity and native elevation. Protein engineering experiments and ancestral- state reconstructions revealed that this …
Repeated Elevational Transitions In Hemoglobin Function During The Evolution Of Andean Hummingbirds, Joana Projecto-Garcia, Chandrasekhar Natarajan, Hideaki Moriyama, Roy E. Weber, Angela Fago, Zachary A. Cheviron, Robert Dudley, Jimmy A. Mcguire, Christopher C. Witt, Jay F. Storz
Repeated Elevational Transitions In Hemoglobin Function During The Evolution Of Andean Hummingbirds, Joana Projecto-Garcia, Chandrasekhar Natarajan, Hideaki Moriyama, Roy E. Weber, Angela Fago, Zachary A. Cheviron, Robert Dudley, Jimmy A. Mcguire, Christopher C. Witt, Jay F. Storz
School of Biological Sciences: Faculty Publications
Animals that sustain high levels of aerobic activity under hypoxic conditions (e.g., birds that fly at high altitude) face the physiological challenge of jointly optimizing blood-O2 affinity for O2 loading in the pulmonary circulation and O2 unloading in the systemic circulation. At high altitude, this challenge is especially acute for small endotherms like hummingbirds that have exceedingly high mass-specific metabolic rates. Here we report an experimental analysis of hemoglobin (Hb) function in South American hummingbirds that revealed a positive correlation between Hb-O2 affinity and native elevation. Protein engineering experiments and ancestral- state reconstructions revealed that this …
Mitochondrial-Nuclear Epistasis Affects Fitness Within Species But Does Not Contribute To Fixed Incompatibilities Between Species Of Drosophila, Kristi L. Montooth, Colin D. Meiklejohn, Dawn N. Abt, David M. Rand
Mitochondrial-Nuclear Epistasis Affects Fitness Within Species But Does Not Contribute To Fixed Incompatibilities Between Species Of Drosophila, Kristi L. Montooth, Colin D. Meiklejohn, Dawn N. Abt, David M. Rand
School of Biological Sciences: Faculty Publications
Efficient mitochondrial function requires physical interactions between the proteins encoded by the mitochondrial and nuclear genomes. Co-evolution between these genomes may result in the accumulation of incompatibilities between divergent lineages. We test whether mitochondrialnuclear incompatibilities have accumulated within the Drosophila melanogaster species subgroup by combining divergent mitochondrial and nuclear lineages and quantifying the effects on relative fitness. Precise placement of nine mtDNAs from D. melanogaster, D. simulans and D. mauritiana into two D. melanogaster nuclear genetic backgrounds reveals significant mitochondrial-nuclear epistasis affecting fitness in females. Combining the mitochondrial genomes with three different D. melanogaster X chromosomes reveals significant epistasis …