Commentary: Hierarchical reductionism approach to understanding adaptive variation in animal performance

Wearing, Oliver H.; Scott, Graham R.

doi:10.1016/j.cbpb.2021.110636

Cited by 4 publications

(2 citation statements)

References 48 publications

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“…3B ). Under severe hypoxia, an increased Hb-O 2 affinity can help safeguard S a O 2 , but this only confers a physiological benefit if tissue O 2 diffusion capacity is sufficiently high that the augmented arterial O 2 content translates into a greater tissue O 2 extraction (Storz & Bautista, 2022; Wearing et al, 2021; Wearing & Scott, 2021). High-altitude vertebrates often have higher Hb-O 2 affinities in comparison with lowland relatives (Storz, 2016, 2019), and this is also true in deer mice, as highland natives from the Rockies have evolved a higher Hb-O 2 affinity than lowland conspecifics from the Great Plains (Jensen et al, 2016; Natarajan et al, 2015; Storz, Runck, et al, 2010; Storz et al, 2009).…”

Section: Resultsmentioning

confidence: 99%

Local adaptation, plasticity, and evolved resistance to hypoxic cold stress in high-altitude deer mice

Bautista,

Herrera,

Shadowitz

et al. 2024

Preprint

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A fundamental question in evolutionary biology concerns the relative contributions of phenotypic plasticity vs. local adaptation (genotypic specialization) in enabling wide-ranging species to inhabit diverse environmental conditions. Here we conduct a long-term hypoxia acclimation experiment to assess the relative roles of local adaptation and plasticity in enabling highland and lowland deer mice (Peromyscus maniculatus) to sustain aerobic thermogenesis at progressively increasing elevations. We assessed the relative physiological performance capacities of highland and lowland natives as they were exposed to progressive, stepwise increases in hypoxia, simulating the gradual ascent from sea level to an elevation of 6000 m. The final elevation of 6000 m far exceeds the highest attainable elevations within the species’ range, and therefore tests the animals’ ability to tolerate levels of hypoxia that surpass the prevailing conditions within their current distributional limits. Our results demonstrate that highland natives exhibit superior thermogenic capacities at the most severe levels of hypoxia, suggesting that the species’ broad fundamental niche and its ability to inhabit such a broad range of elevational zones is attributable to a combination of genetically based local adaptation and plasticity. Transcriptomic and physiological measurements identify evolved changes in the acclimation response to hypoxia that contribute to the enhanced thermogenic capacity of highland natives.SIGNIFICANCE STATEMENTIn species that are distributed across steep environmental gradients, the ability to inhabit a broad range of conditions may be attributable to local adaptation and/or a generalized acclimatization capacity (phenotypic plasticity). By experimentally acclimating highland and lowland deer mice (Peromyscus maniculatus) to progressively increasing levels of hypoxia during a simulated ascent to 6000 m, we assessed the relative roles of evolved and plastic changes in thermogenic capacity. At especially severe levels of hypoxia, the superior thermogenic performance of highland natives relative to lowland conspecifics suggests that the broad fundamental niche of deer mice is largely attributable to local adaptation to different elevational zones, including evolved plasticity in gene expression and respiratory traits.

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Section: Resultsmentioning

confidence: 99%

Local adaptation, plasticity, and evolved resistance to hypoxic cold stress in high-altitude deer mice

Bautista,

Herrera,

Shadowitz

et al. 2024

Preprint

Self Cite

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“…The mechanisms underlying the evolution of complex performance traits is a central and unresolved topic in evolutionary physiology ( Dalziel et al, 2009 ; Garland et al, 2016 ; Garland and Carter, 1994 ; Scott and Dalziel, 2021 ). Studies of aerobic performance in endotherms that are native to high altitude can shed valuable insight into this topic ( McClelland and Scott, 2019 ; Monge and Leon-Velarde, 1991 ; Storz, 2021 ; Storz et al, 2015 ; Wearing and Scott, 2021 ). High-altitude environments are cold and hypoxic, which challenges the ability of endotherms to maintain sufficient rates of O 2 supply to meet the O 2 demands of thermogenesis and locomotion.…”

Section: Introductionmentioning

confidence: 99%

Adrenergic control of the cardiovascular system in deer mice native to high altitude

Wearing

Nelson

Ivy

et al. 2022

Current Research in Physiology

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Studies of animals native to high altitude can provide valuable insight into physiological mechanisms and evolution of performance in challenging environments. We investigated how mechanisms controlling cardiovascular function may have evolved in deer mice ( Peromyscus maniculatus ) native to high altitude. High-altitude deer mice and low-altitude white-footed mice ( P. leucopus ) were bred in captivity at sea level, and first-generation lab progeny were raised to adulthood and acclimated to normoxia or hypoxia. We then used pharmacological agents to examine the capacity for adrenergic receptor stimulation to modulate heart rate ( f H ) and mean arterial pressure ( P mean ) in anaesthetized mice, and used cardiac pressure-volume catheters to evaluate the contractility of the left ventricle. We found that highlanders had a consistently greater capacity to increase f H via pharmacological stimulation of β 1 -adrenergic receptors than lowlanders. Also, whereas hypoxia acclimation reduced the capacity for increasing P mean in response to α-adrenergic stimulation in lowlanders, highlanders exhibited no plasticity in this capacity. These differences in highlanders may help augment cardiac output during locomotion or cold stress, and may preserve their capacity for α-mediated vasoconstriction to more effectively redistribute blood flow to active tissues. Highlanders did not exhibit any differences in some measures of cardiac contractility (maximum pressure derivative, d P /dt max , or end-systolic elastance, E es ), but ejection fraction was highest in highlanders after hypoxia acclimation. Overall, our results suggest that evolved changes in sensitivity to adrenergic stimulation of cardiovascular function may help deer mice cope with the cold and hypoxic conditions at high altitude.

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Altitude acclimatization, hemoglobin-oxygen affinity, and circulatory oxygen transport in hypoxia

Storz

Bautista

2022

Molecular Aspects of Medicine

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Commentary: Hierarchical reductionism approach to understanding adaptive variation in animal performance

Cited by 4 publications

References 48 publications

Local adaptation, plasticity, and evolved resistance to hypoxic cold stress in high-altitude deer mice

Local adaptation, plasticity, and evolved resistance to hypoxic cold stress in high-altitude deer mice

Adrenergic control of the cardiovascular system in deer mice native to high altitude

Altitude acclimatization, hemoglobin-oxygen affinity, and circulatory oxygen transport in hypoxia

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