1
|
Graham AM, Lavretsky P, Wilson RE, McCracken KG. High-altitude adaptation is accompanied by strong signatures of purifying selection in the mitochondrial genomes of three Andean waterfowl. PLoS One 2024; 19:e0294842. [PMID: 38170710 PMCID: PMC10763953 DOI: 10.1371/journal.pone.0294842] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 11/09/2023] [Indexed: 01/05/2024] Open
Abstract
Evidence from a variety of organisms points to convergent evolution on the mitochondria associated with a physiological response to oxygen deprivation or temperature stress, including mechanisms for high-altitude adaptation. Here, we examine whether demography and/or selection explains standing mitogenome nucleotide diversity in high-altitude adapted populations of three Andean waterfowl species: yellow-billed pintail (Anas georgica), speckled teal (Anas flavirostris), and cinnamon teal (Spatula cyanoptera). We compared a total of 60 mitogenomes from each of these three duck species (n = 20 per species) across low and high altitudes and tested whether part(s) or all of the mitogenome exhibited expected signatures of purifying selection within the high-altitude populations of these species. Historical effective population sizes (Ne) were inferred to be similar between high- and low-altitude populations of each species, suggesting that selection rather than genetic drift best explains the reduced genetic variation found in mitochondrial genes of high-altitude populations compared to low-altitude populations of the same species. Specifically, we provide evidence that establishment of these three Andean waterfowl species in the high-altitude environment, coincided at least in part with a persistent pattern of negative purifying selection acting on oxidative phosphorylation (OXPHOS) function of the mitochondria. Our results further reveal that the extent of gene-specific purifying selection has been greatest in the speckled teal, the species with the longest history of high-altitude occupancy.
Collapse
Affiliation(s)
- Allie M. Graham
- Eccles Institute for Human Genetics, University of Utah, Salt Lake City, UT, United States of America
| | - Philip Lavretsky
- Department of Biological Sciences, University of Texas at El Paso, El Paso, TX, United States of America
| | - Robert E. Wilson
- School of Natural Resources and Nebraska State Museum, University of Nebraska–Lincoln, Lincoln, NE, United States of America
| | - Kevin G. McCracken
- Department of Biology, University of Miami, Coral Gables, FL, United States of America
- Department of Marine Biology and Ecology, Rosenstiel School of Marine, Atmospheric, and Earth Science, University of Miami, Miami, FL, United States of America
- Human Genetics and Genomics, University of Miami Miller School of Medicine, Miami, FL, United States of America
- University of Alaska Museum, University of Alaska Fairbanks, Fairbanks, AK, United States of America
| |
Collapse
|
2
|
Palacios C, Wang P, Wang N, Brown MA, Capatosto L, Du J, Jiang J, Zhang Q, Dahal N, Lamichhaney S. Genomic Variation, Population History, and Long-Term Genetic Adaptation to High Altitudes in Tibetan Partridge (Perdix hodgsoniae). Mol Biol Evol 2023; 40:msad214. [PMID: 37768198 PMCID: PMC10583571 DOI: 10.1093/molbev/msad214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 09/09/2023] [Accepted: 09/25/2023] [Indexed: 09/29/2023] Open
Abstract
Species residing across elevational gradients display adaptations in response to environmental changes such as oxygen availability, ultraviolet radiation, and temperature. Here, we study genomic variation, gene expression, and long-term adaptation in Tibetan Partridge (Perdix hodgsoniae) populations residing across the elevational gradient of the Tibetan Plateau. We generated a high-quality draft genome and used it to carry out downstream population genomic and transcriptomic analysis. The P. hodgsoniae populations residing across various elevations were genetically distinct, and their phylogenetic clustering was consistent with their geographic distribution. We identified possible evidence of gene flow between populations residing in <3,000 and >4,200 m elevation that is consistent with known habitat expansion of high-altitude populations of P. hodgsoniae to a lower elevation. We identified a 60 kb haplotype encompassing the Estrogen Receptor 1 (ESR1) gene, showing strong genetic divergence between populations of P. hodgsoniae. We identified six single nucleotide polymorphisms within the ESR1 gene fixed for derived alleles in high-altitude populations that are strongly conserved across vertebrates. We also compared blood transcriptome profiles and identified differentially expressed genes (such as GAPDH, LDHA, and ALDOC) that correlated with differences in altitude among populations of P. hodgsoniae. These candidate genes from population genomics and transcriptomics analysis were enriched for neutrophil degranulation and glycolysis pathways, which are known to respond to hypoxia and hence may contribute to long-term adaptation to high altitudes in P. hodgsoniae. Our results highlight Tibetan Partridges as a useful model to study molecular mechanisms underlying long-term adaptation to high altitudes.
Collapse
Affiliation(s)
- Catalina Palacios
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Pengcheng Wang
- Jiangsu Key Laboratory for Biodiversity and Biotechnology, College of Life Sciences, Nanjing Normal University, Nanjing 210023, P. R. China
| | - Nan Wang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, P. R. China
| | - Megan A Brown
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Lukas Capatosto
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Juan Du
- Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, P. R. China
| | - Jiahu Jiang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, P. R. China
| | - Qingze Zhang
- School of Ecology and Nature Conservation, Beijing Forestry University, Beijing 100083, P. R. China
| | - Nishma Dahal
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, HP 176061, India
| | - Sangeet Lamichhaney
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| |
Collapse
|
3
|
Ivy CM, Guglielmo CG. Migratory songbirds exhibit seasonal modulation of the oxygen cascade. J Exp Biol 2023; 226:jeb245975. [PMID: 37534524 PMCID: PMC10482389 DOI: 10.1242/jeb.245975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Accepted: 07/31/2023] [Indexed: 08/04/2023]
Abstract
Migratory flight requires birds to maintain intensive aerobic exercise for many hours or days. Maintaining O2 supply to flight muscles is therefore important during migration, especially since migratory songbirds have been documented flying at altitudes greater than 5000 m above sea level, where O2 is limited. Whether songbirds exhibit seasonal plasticity of the O2 cascade to maintain O2 uptake and transport during migratory flight is not well understood. We investigated changes in the hypoxic ventilatory response, haematology and pectoralis (flight) muscle phenotype of 6 songbird species from 3 families during migratory and non-migratory conditions. Songbirds were captured during southbound migration in southern Ontario, Canada. Half of the birds were assessed during migration, and the rest were transitioned onto a winter photoperiod to induce a non-migratory phenotype and measured. All species exhibited seasonal plasticity at various stages along the O2 cascade, but not all species exhibited the same responses. Songbirds tended to be more hypoxia tolerant during migration, withstanding 5 kPa O2 and breathed more effectively through slower, deeper breaths. Warblers had a stronger haemoglobin-O2 affinity during autumn migration (decrease of ∼4.7 Torr), while the opposite was observed in thrushes (increase of ∼2.6 Torr). In the flight muscle there was an ∼1.2-fold increase in the abundance of muscle fibres with smaller fibre transverse areas during autumn migration, but no changes in capillary:fibre ratio. These adjustments would enhance O2 uptake and transport to the flight muscle. Our findings demonstrate that in the O2 cascade there is no ideal migratory phenotype for all songbirds.
Collapse
Affiliation(s)
- Catherine M. Ivy
- Department of Biology, Advanced Facility for Avian Research, Western University, London, ON, Canada, N6A 3K7
| | - Christopher G. Guglielmo
- Department of Biology, Advanced Facility for Avian Research, Western University, London, ON, Canada, N6A 3K7
| |
Collapse
|
4
|
Yu JJ, Non AL, Heinrich EC, Gu W, Alcock J, Moya EA, Lawrence ES, Tift MS, O'Brien KA, Storz JF, Signore AV, Khudyakov JI, Milsom WK, Wilson SM, Beall CM, Villafuerte FC, Stobdan T, Julian CG, Moore LG, Fuster MM, Stokes JA, Milner R, West JB, Zhang J, Shyy JY, Childebayeva A, Vázquez-Medina JP, Pham LV, Mesarwi OA, Hall JE, Cheviron ZA, Sieker J, Blood AB, Yuan JX, Scott GR, Rana BK, Ponganis PJ, Malhotra A, Powell FL, Simonson TS. Time Domains of Hypoxia Responses and -Omics Insights. Front Physiol 2022; 13:885295. [PMID: 36035495 PMCID: PMC9400701 DOI: 10.3389/fphys.2022.885295] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023] Open
Abstract
The ability to respond rapidly to changes in oxygen tension is critical for many forms of life. Challenges to oxygen homeostasis, specifically in the contexts of evolutionary biology and biomedicine, provide important insights into mechanisms of hypoxia adaptation and tolerance. Here we synthesize findings across varying time domains of hypoxia in terms of oxygen delivery, ranging from early animal to modern human evolution and examine the potential impacts of environmental and clinical challenges through emerging multi-omics approaches. We discuss how diverse animal species have adapted to hypoxic environments, how humans vary in their responses to hypoxia (i.e., in the context of high-altitude exposure, cardiopulmonary disease, and sleep apnea), and how findings from each of these fields inform the other and lead to promising new directions in basic and clinical hypoxia research.
Collapse
Affiliation(s)
- James J. Yu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Amy L. Non
- Department of Anthropology, Division of Social Sciences, University of California, San Diego, La Jolla, CA, United States,*Correspondence: Amy L. Non, Tatum S. Simonson,
| | - Erica C. Heinrich
- Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, United States
| | - Wanjun Gu
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States,Herbert Wertheim School of Public Health and Longevity Sciences, University of California, San Diego, La Jolla, CA, United States
| | - Joe Alcock
- Department of Emergency Medicine, University of New Mexico, Albuquerque, MX, United States
| | - Esteban A. Moya
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Elijah S. Lawrence
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Michael S. Tift
- Department of Biology and Marine Biology, College of Arts and Sciences, University of North Carolina Wilmington, Wilmington, NC, United States
| | - Katie A. O'Brien
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States,Department of Physiology, Development and Neuroscience, Faculty of Biology, School of Biological Sciences, University of Cambridge, Cambridge, ENG, United Kingdom
| | - Jay F. Storz
- School of Biological Sciences, College of Arts and Sciences, University of Nebraska-Lincoln, Lincoln, IL, United States
| | - Anthony V. Signore
- School of Biological Sciences, College of Arts and Sciences, University of Nebraska-Lincoln, Lincoln, IL, United States
| | - Jane I. Khudyakov
- Department of Biological Sciences, University of the Pacific, Stockton, CA, United States
| | | | - Sean M. Wilson
- Lawrence D. Longo, MD Center for Perinatal Biology, Loma Linda, CA, United States
| | | | | | | | - Colleen G. Julian
- School of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Lorna G. Moore
- Division of Reproductive Sciences, Department of Obstetrics and Gynecology, Aurora, CO, United States
| | - Mark M. Fuster
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Jennifer A. Stokes
- Department of Kinesiology, Southwestern University, Georgetown, TX, United States
| | - Richard Milner
- San Diego Biomedical Research Institute, San Diego, CA, United States
| | - John B. West
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Jiao Zhang
- Department of Medicine, UC San Diego School of Medicine, San Diego, CA, United States
| | - John Y. Shyy
- Department of Medicine, UC San Diego School of Medicine, San Diego, CA, United States
| | - Ainash Childebayeva
- Department of Archaeogenetics, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany
| | - José Pablo Vázquez-Medina
- Department of Integrative Biology, College of Letters and Science, University of California, Berkeley, Berkeley, CA, United States
| | - Luu V. Pham
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, School of Medicine, Johns Hopkins Medicine, Baltimore, MD, United States
| | - Omar A. Mesarwi
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - James E. Hall
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Zachary A. Cheviron
- Division of Biological Sciences, College of Humanities and Sciences, University of Montana, Missoula, MT, United States
| | - Jeremy Sieker
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Arlin B. Blood
- Department of Pediatrics Division of Neonatology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Jason X. Yuan
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Graham R. Scott
- Department of Pediatrics Division of Neonatology, School of Medicine, Loma Linda University, Loma Linda, CA, United States
| | - Brinda K. Rana
- Moores Cancer Center, UC San Diego, La Jolla, CA, United States,Department of Psychiatry, UC San Diego, La Jolla, CA, United States
| | - Paul J. Ponganis
- Center for Marine Biotechnology and Biomedicine, La Jolla, CA, United States
| | - Atul Malhotra
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Frank L. Powell
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States
| | - Tatum S. Simonson
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, University of California, San Diego, La Jolla, CA, United States,*Correspondence: Amy L. Non, Tatum S. Simonson,
| |
Collapse
|
5
|
Zhang Y, Montgomery DW, White CF, Richards JG, Brauner CJ, Farrell AP. Characterizing the hypoxic performance of a fish using a new metric: PAAS-50. J Exp Biol 2022; 225:275279. [PMID: 35502769 DOI: 10.1242/jeb.244239] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 04/27/2022] [Indexed: 11/20/2022]
Abstract
The hypoxic constraint on peak oxygen uptake (ṀO2peak) was characterized in rainbow trout over a range of ambient oxygen tensions with different testing protocols and statistical models. The best-fit model was selected using both statistical criteria (R2 & AIC) and the model's prediction of three anchor points for hypoxic performance: critical PO2 (Pcrit), maximum ṀO2 and a new metric, the minimum PO2 that supports 50% of absolute aerobic scope (PAAS-50). The best-fitting model was curvilinear using five strategically selected PO2 values. This model predicted PAAS-50 as 70 mm Hg (CV=9%) for rainbow trout. Thus, while a five-point hypoxic performance curve can characterize the limiting effects of hypoxia in fish, as envisioned by Fry over 75 years ago, PAAS-50 is a promising metric to compare hypoxic constraints on performance in a standardized manner both within and across fish species.
Collapse
Affiliation(s)
- Yangfan Zhang
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, VT6 1Z4, Canada.,Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, Massachusetts, 02138, USA
| | - Daniel W Montgomery
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, VT6 1Z4, Canada
| | - Connor F White
- Department of Organismic and Evolutionary Biology, Harvard University, 26 Oxford St, Cambridge, Massachusetts, 02138, USA
| | - Jeffrey G Richards
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, VT6 1Z4, Canada
| | - Colin J Brauner
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, VT6 1Z4, Canada
| | - Anthony P Farrell
- Department of Zoology and Faculty of Land and Food Systems, University of British Columbia, Vancouver, British Columbia, VT6 1Z4, Canada
| |
Collapse
|
6
|
Joyce W, Wang T. Regulation of heart rate in vertebrates during hypoxia: A comparative overview. Acta Physiol (Oxf) 2022; 234:e13779. [PMID: 34995393 DOI: 10.1111/apha.13779] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/12/2021] [Accepted: 01/01/2022] [Indexed: 12/18/2022]
Abstract
Acute exposure to low oxygen (hypoxia) places conflicting demands on the heart. Whilst an increase in heart rate (tachycardia) may compensate systemic oxygen delivery as arterial oxygenation falls, the heart itself is an energetically expensive organ that may benefit from slowing (bradycardia) to reduce work when oxygen is limited. Both strategies are apparent in vertebrates, with tetrapods (mammals, birds, reptiles, and amphibians) classically exhibiting hypoxic tachycardia and fishes displaying characteristic hypoxic bradycardia. With a richer understanding of the ontogeny and evolution of the responses, however, we see similarities in the underlying mechanisms between vertebrate groups. For example, in adult mammals, primary bradycardia results from the hypoxic stimulation of carotid body chemoreceptors that are overwhelmed by mechano-sensory feedback from the lung associated with hyperpnoea. Fish-like bradycardia prevails in the mammalian foetus (which, at this stage, is incapable of pulmonary ventilation), and in fish and foetus alike, the bradycardia ensues despite an elevation of circulating catecholamines. In both cases, the reduced heart rate may primarily serve to protect the heart. Thus, the comparative perspective offers fundamental insight into how and why different vertebrates regulate heart rate in different ways during periods of hypoxia.
Collapse
Affiliation(s)
- William Joyce
- Department of Biology—Zoophysiology Aarhus University Aarhus C Denmark
| | - Tobias Wang
- Department of Biology—Zoophysiology Aarhus University Aarhus C Denmark
| |
Collapse
|
7
|
Cardenas T, Naoki K, Landivar CM, Struelens Q, Gómez MI, Meneses RI, Cauvy‐Fraunié S, Anthelme F, Dangles O. Glacier influence on bird assemblages in habitat islands of the high Bolivian Andes. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Affiliation(s)
- Tatiana Cardenas
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE Univ Montpellier, CNRS, EPHE, IRD Montpellier France
| | - Kazuya Naoki
- Instituto de Ecología Universidad Mayor de San Andrés La Paz Bolivia
| | | | - Quentin Struelens
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE Univ Montpellier, CNRS, EPHE, IRD Montpellier France
- Muséum National d’Histoire Naturelle Sorbonne Universités Paris France
| | | | | | | | - Fabien Anthelme
- AMAP, IRD, CIRAD, CNRS, INRA Université de Montpellier Montpellier France
| | - Olivier Dangles
- Centre d'Ecologie Fonctionnelle et Evolutive CEFE Univ Montpellier, CNRS, EPHE, IRD Montpellier France
| |
Collapse
|
8
|
Polymeropoulos ET, Milsom WK. Editorial: Untangling the oxygen transport cascade: a tribute to Peter Frappell (Frapps). J Comp Physiol B 2021; 191:973-978. [PMID: 34463812 DOI: 10.1007/s00360-021-01401-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/15/2021] [Accepted: 08/18/2021] [Indexed: 10/20/2022]
Abstract
This collection of research articles was put together in honour of respiratory physiologist Professor Peter Frappell's (Frapps's) academic achievements. It encompasses various topics relating to the oxygen transport cascade, which was central to Frapps' career as a comparative physiologist. This issue highlights the diversity and outreach of his influence on the field and his pioneering spirit; promoting novel perspectives, methodologies and research techniques. This issue also demonstrates how Frapps' knowledge and scientific findings answered some of the fundamental questions within the field of respiratory physiology while creating and fostering a rather unique work atmosphere in the laboratories he led. We thank Frapps for the contributions he has made and the friendships he has nurtured over his career. Cheers, Frapps - we love you mate!
Collapse
Affiliation(s)
- Elias T Polymeropoulos
- Institute for Marine and Antarctic Studies (IMAS), University of Tasmania, Hobart, TAS, 7001, Australia.
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada
| |
Collapse
|
9
|
Ivy CM, Scott GR. Life-long exposure to hypoxia affects metabolism and respiratory physiology across life stages in high-altitude deer mice ( Peromyscus maniculatus). ACTA ACUST UNITED AC 2021; 224:jeb.237024. [PMID: 33268530 DOI: 10.1242/jeb.237024] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 11/24/2020] [Indexed: 12/12/2022]
Abstract
Hypoxia exposure can have distinct physiological effects between early developmental and adult life stages, but it is unclear how the effects of hypoxia may progress during continuous exposure throughout life. We examined this issue in deer mice (Peromyscus maniculatus) from a population native to high altitude. Mice were bred in captivity in one of three treatment groups: normoxia (controls), life-long hypoxia (∼12 kPa O2 from conception to adulthood) and parental hypoxia (normoxia from conception to adulthood, but parents previously exposed to hypoxia). Metabolic, thermoregulatory and ventilatory responses to progressive stepwise hypoxia and haematology were then measured at post-natal day (P) 14 and 30 and/or in adulthood. Life-long hypoxia had consistent effects across ages on metabolism, attenuating the declines in O2 consumption rate (V̇ O2 ) and body temperature during progressive hypoxia compared with control mice. However, life-long hypoxia had age-specific effects on breathing, blunting the hypoxia-induced increases in air convection requirement (quotient of total ventilation and V̇ O2 ) at P14 and P30 only, but then shifting breathing pattern towards deeper and/or less frequent breaths at P30 and adulthood. Hypoxia exposure also increased blood-O2 affinity at P14 and P30, in association with an increase in arterial O2 saturation in hypoxia at P30. In contrast, parental hypoxia had no effects on metabolism or breathing, but it increased blood-O2 affinity and decreased red cell haemoglobin content at P14 (but not P30). Therefore, hypoxia exposure has some consistent effects across early life and adulthood, and some other effects that are unique to specific life stages.
Collapse
Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| |
Collapse
|
10
|
Milsom WK, Scott GR, Frappell PB, McCracken KG. Different strategies for convective O 2 transport in high altitude birds: A graphical analysis. Comp Biochem Physiol A Mol Integr Physiol 2020; 253:110871. [PMID: 33321176 DOI: 10.1016/j.cbpa.2020.110871] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 11/16/2022]
Abstract
For illustrative purposes, in this article we use "Johansen Plots" as a graphical way of simultaneously visualizing the inter-connected variables that compose the convective steps of the gas transport cascade. These plots are used to reflect on some of the physiological characteristics seen in five species of birds, four of which sojourn to, or are native to, high altitudes (the barnacle goose, bar-headed goose, Andean goose, speckled teal and ruddy duck). These species were chosen to emphasize the diversity of responses to hypoxia that can exist within a single family. This diversity likely arose for many possible reasons, including local adaptation to hypoxia, differences in flight or diving abilities, or as a result of other phylogenetically-based differences across waterfowl in physiology, behaviour, and/or life style.
Collapse
Affiliation(s)
- W K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - G R Scott
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | | | - K G McCracken
- Department of Biology, Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA
| |
Collapse
|
11
|
Li D, Davison G, Lisovski S, Battley PF, Ma Z, Yang S, How CB, Watkins D, Round P, Yee A, Srinivasan V, Teo C, Teo R, Loo A, Leong CC, Er K. Shorebirds wintering in Southeast Asia demonstrate trans-Himalayan flights. Sci Rep 2020; 10:21232. [PMID: 33311583 PMCID: PMC7732824 DOI: 10.1038/s41598-020-77897-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023] Open
Abstract
Many birds wintering in the Indian subcontinent fly across the Himalayas during migration, including Bar-headed Geese (Anser indicus), Demoiselle Cranes (Anthropoides virgo) and Ruddy Shelducks (Tadorna ferruginea). However, little is known about whether shorebirds migrate across the Himalayas from wintering grounds beyond the Indian subcontinent. Using geolocators and satellite tracking devices, we demonstrate for the first time that Common Redshanks (Tringa totanus) and Whimbrels (Numenius phaeopus) wintering in Singapore can directly fly over the Himalayas to reach breeding grounds in the Qinghai-Tibet Plateau and north-central Russia respectively. The results also show that migratory shorebirds wintering in Southeast Asia can use both the Central Asian Flyway and the East Asian-Australasian Flyway. For Redshanks, westerly-breeding birds crossed the Himalayas while more easterly breeders on the Plateau migrated east of the Himalayas. For Whimbrels, an individual that crossed the Himalayas was probably from a breeding population that was different from the others that migrated along the coast up the East Asian-Australasian Flyway. The minimum required altitude of routes of trans-Himalayan Redshanks were no higher on average than those of eastern migrants, but geolocator temperature data indicate that birds departing Singapore flew at high elevations even when not required to by topography, suggesting that the Himalayan mountain range may be less of a barrier than assumed.
Collapse
Affiliation(s)
- David Li
- National Parks Board, Singapore, 718925, Singapore.
| | | | - Simeon Lisovski
- Alfred-Wegener-Institute Helmholtz Centre for Marine and Polar Research, Potsdam, Germany
| | - Phil F Battley
- Wildlife & Ecology Group, Massey University, Palmerston North, 4442, New Zealand
| | - Zhijun Ma
- Ministry of Education Key Laboratory for Biodiversity Science and Ecological Engineering, Coastal Ecosystems Research Station of the Yangtze River Estuary, Institute of Biodiversity Science, School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Shufen Yang
- National Parks Board, Singapore, 718925, Singapore
| | | | - Doug Watkins
- Australasian Wader Studies Group, Carlton, VIC, 3053, Australia
| | - Philip Round
- Department of Biology, Mahidol University, Bangkok, 10400, Thailand
| | - Alex Yee
- National Parks Board, Singapore, 718925, Singapore
| | | | - Clarice Teo
- National Parks Board, Singapore, 718925, Singapore
| | - Robert Teo
- National Parks Board, Singapore, 718925, Singapore
| | - Adrian Loo
- National Parks Board, Singapore, 718925, Singapore
| | | | - Kenneth Er
- National Parks Board, Singapore, 718925, Singapore
| |
Collapse
|
12
|
Dawson NJ, Alza L, Nandal G, Scott GR, McCracken KG. Convergent changes in muscle metabolism depend on duration of high-altitude ancestry across Andean waterfowl. eLife 2020; 9:e56259. [PMID: 32729830 PMCID: PMC7494360 DOI: 10.7554/elife.56259] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 07/23/2020] [Indexed: 01/07/2023] Open
Abstract
High-altitude environments require that animals meet the metabolic O2 demands for locomotion and thermogenesis in O2-thin air, but the degree to which convergent metabolic changes have arisen across independent high-altitude lineages or the speed at which such changes arise is unclear. We examined seven high-altitude waterfowl that have inhabited the Andes (3812-4806 m elevation) over varying evolutionary time scales, to elucidate changes in biochemical pathways of energy metabolism in flight muscle relative to low-altitude sister taxa. Convergent changes across high-altitude taxa included increased hydroxyacyl-coA dehydrogenase and succinate dehydrogenase activities, decreased lactate dehydrogenase, pyruvate kinase, creatine kinase, and cytochrome c oxidase activities, and increased myoglobin content. ATP synthase activity increased in only the longest established high-altitude taxa, whereas hexokinase activity increased in only newly established taxa. Therefore, changes in pathways of lipid oxidation, glycolysis, and mitochondrial oxidative phosphorylation are common strategies to cope with high-altitude hypoxia, but some changes require longer evolutionary time to arise.
Collapse
Affiliation(s)
- Neal J Dawson
- Department of Biology, McMaster UniversityHamiltonCanada
- Department of Biology University of MiamiCoral GablesUnited States
| | - Luis Alza
- Department of Biology University of MiamiCoral GablesUnited States
- University of Alaska Museum and Institute of Arctic Biology, University of Alaska FairbanksFairbanksUnited States
- Centro de Ornitología y Biodiversidad - CORBIDILimaPeru
| | | | - Graham R Scott
- Department of Biology, McMaster UniversityHamiltonCanada
| | - Kevin G McCracken
- Department of Biology University of MiamiCoral GablesUnited States
- University of Alaska Museum and Institute of Arctic Biology, University of Alaska FairbanksFairbanksUnited States
- Centro de Ornitología y Biodiversidad - CORBIDILimaPeru
- Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of MiamiMiamiUnited States
- Human Genetics and Genomics, Hussman Institute for Human Genomics, University of Miami Miller School of MedicineMiamiUnited States
| |
Collapse
|
13
|
Bakkeren C, Smith E, York JM, Chua B, McCracken KG, Milsom WK. A morphometric analysis of the lungs of high-altitude ducks and geese. J Anat 2020; 237:188-196. [PMID: 32173858 PMCID: PMC7309286 DOI: 10.1111/joa.13180] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/12/2020] [Accepted: 02/18/2020] [Indexed: 02/06/2023] Open
Abstract
We examined the morphology of the lungs of five species of high-altitude resident ducks from Lake Titicaca in the Peruvian Andes (yellow-billed pintail [Anas georgica], cinnamon teal [Anas cyanoptera orinomus], puna teal [Anas puna], speckled teal [Anas flavirostris oxyptera], and ruddy duck [Oxyura jamaicensis ferruginea]) and compared them with those of the high-altitude migratory bar-headed goose (Anser indicus) and the low-altitude migratory barnacle goose (Branta leucopsis). We then determined the relationship between mass-specific lung volume, the volume densities of the component parts of the lung, and previously reported hypoxia-induced increases in pulmonary O2 extraction. We found that the mass-specific lung volumes and the mass-specific volume of the exchange tissue were larger in the lungs of high-altitude resident birds. The bar-headed goose had a mass-specific lung volume that fell between those of the low-altitude species and the high-altitude residents, but a mass-specific volume of exchange tissue that was not significantly different than that of the high-altitude residents. The data suggest that the mass-specific volume of the lung may increase with evolutionary time spent at altitude. We found an inverse relationship between the percentage increase in pulmonary O2 extraction and the percentage increase in ventilation across species that was independent of the volume density of the exchange tissue, at least for the resident Andean birds.
Collapse
Affiliation(s)
- Ciska Bakkeren
- Department of ZoologyUniversity of British ColumbiaVancouverBCCanada
| | - Emily Smith
- Department of ZoologyUniversity of British ColumbiaVancouverBCCanada
| | - Julia M. York
- Department of Integrative BiologyUniversity of Texas at AustinAustinTXUSA
| | - Beverly Chua
- Department of ZoologyUniversity of British ColumbiaVancouverBCCanada
| | - Kevin G. McCracken
- Department of BiologyRosenstiel School of Marine and Atmospheric SciencesUniversity of MiamiCoral GablesFLUSA
- Department of Marine Biology and EcologyRosenstiel School of Marine and Atmospheric SciencesUniversity of MiamiCoral GablesFLUSA
- Human Genetics and GenomicsUniversity of Miami Miller School of MedicineUniversity of MiamiCoral GablesFLUSA
- University of Alaska Museum and Institute of Arctic BiologyUniversity of Alaska FairbanksFairbanksAKUSA
| | - William K. Milsom
- Department of ZoologyUniversity of British ColumbiaVancouverBCCanada
| |
Collapse
|
14
|
Ivy CM, Greaves MA, Sangster ED, Robertson CE, Natarajan C, Storz JF, McClelland GB, Scott GR. Ontogenesis of evolved changes in respiratory physiology in deer mice native to high altitude. J Exp Biol 2020; 223:jeb219360. [PMID: 32054682 PMCID: PMC7075075 DOI: 10.1242/jeb.219360] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 02/07/2020] [Indexed: 01/08/2023]
Abstract
High-altitude environments are cold and hypoxic, and many high-altitude natives have evolved changes in respiratory physiology that improve O2 uptake in hypoxia as adults. Altricial mammals undergo a dramatic metabolic transition from ectothermy to endothermy in early post-natal life, which may influence the ontogenetic development of respiratory traits at high altitude. We examined the developmental changes in respiratory and haematological traits in deer mice (Peromyscus maniculatus) native to high altitude, comparing the respiratory responses to progressive hypoxia between highland and lowland deer mice. Among adults, highlanders exhibited higher total ventilation and a more effective breathing pattern (relatively deeper tidal volumes), for mice that were caught and tested at their native altitudes and those lab-raised in normoxia. Lab-raised progeny of each population were also tested at post-natal day (P)7, 14, 21 and 30. Highlanders developed an enhanced hypoxic ventilatory response by P21, concurrent with the full maturation of the carotid bodies, and their more effective breathing pattern arose by P14; these ages correspond to critical benchmarks in the full development of homeothermy in highlanders. However, highlanders exhibited developmental delays in ventilatory sensitivity to hypoxia, hyperplasia of type I cells in the carotid body and increases in blood haemoglobin content compared with lowland mice. Nevertheless, highlanders maintained consistently higher arterial O2 saturation in hypoxia across development, in association with increases in blood-O2 affinity that were apparent from birth. We conclude that evolved changes in respiratory physiology in high-altitude deer mice become expressed in association with the post-natal development of endothermy.
Collapse
Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Mary A Greaves
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | | | | | | | - Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, NE 68588, USA
| | - Grant B McClelland
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON L8S 4K1, Canada
| |
Collapse
|
15
|
Abstract
In the 1950s, Arthur C. Guyton removed the heart from its pedestal in cardiovascular physiology by arguing that cardiac output is primarily regulated by the peripheral vasculature. This is counterintuitive, as modulating heart rate would appear to be the most obvious means of regulating cardiac output. In this Review, we visit recent and classic advances in comparative physiology in light of this concept. Although most vertebrates increase heart rate when oxygen demands rise (e.g. during activity or warming), experimental evidence suggests that this tachycardia is neither necessary nor sufficient to drive a change in cardiac output (i.e. systemic blood flow, Q̇ sys) under most circumstances. Instead, Q̇ sys is determined by the interplay between vascular conductance (resistance) and capacitance (which is mainly determined by the venous circulation), with a limited and variable contribution from heart function (myocardial inotropy). This pattern prevails across vertebrates; however, we also highlight the unique adaptations that have evolved in certain vertebrate groups to regulate venous return during diving bradycardia (i.e. inferior caval sphincters in diving mammals and atrial smooth muscle in turtles). Going forward, future investigation of cardiovascular responses to altered metabolic rate should pay equal consideration to the factors influencing venous return and cardiac filling as to the factors dictating cardiac function and heart rate.
Collapse
Affiliation(s)
- William Joyce
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark .,Department of Biology, University of Ottawa, 30 Marie Curie, Ottawa, ON K1N 6N5, Canada
| | - Tobias Wang
- Zoophysiology, Department of Bioscience, Aarhus University, 8000 Aarhus C, Denmark
| |
Collapse
|
16
|
Lague SL, Ivy CM, York JM, Chua BA, Alza L, Cheek R, Dawson NJ, Frappell PB, Farrell AP, McCracken KG, Scott GR, Milsom WK. Cardiovascular responses to progressive hypoxia in ducks native to high altitude in the Andes. J Exp Biol 2020:jeb.211250. [PMID: 34005543 DOI: 10.1242/jeb.211250] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 02/02/2020] [Indexed: 02/24/2024]
Abstract
The cardiovascular system is critical for delivering O2 to tissues. Here we examine the cardiovascular responses to progressive hypoxia in four high-altitude Andean duck species compared to four related low-altitude populations in North America, tested at their native altitude. Ducks were exposed to stepwise decreases in inspired partial pressure of O2 while we monitored heart rate, O2 consumption rate, blood O2 saturation, haematocrit (Hct), and blood haemoglobin concentration [Hb]. We calculated O2 pulse (the product of stroke volume and the arterial-venous O2 content difference), blood O2 concentration, and heart rate variability. Regardless of altitude, all eight populations maintained O2 consumption rate with minimal change in heart rate or O2 pulse, indicating that O2 consumption was maintained by either a constant arterial-venous O2 content difference (an increase in the relative O2 extracted from arterial blood) or by a combination of changes in stroke volume and the arterial-venous O2 content difference. Three high-altitude taxa (yellow-billed pintails, cinnamon teal, and speckled teal) had higher Hct and [Hb], increasing the O2 content of arterial blood, and potentially providing a greater reserve for enhancing O2 delivery during hypoxia. Hct and [Hb] between low- and high-altitude populations of ruddy duck were similar, representing a potential adaptation to diving life. Heart rate variability was generally lower in high-altitude ducks, concurrent with similar or lower heart rates than low-altitude ducks, suggesting a reduction in vagal and sympathetic tone. These unique features of the Andean ducks differ from previous observations in both Andean geese and bar-headed geese, neither of which exhibit significant elevations in Hct or [Hb] compared to their low-altitude relatives, revealing yet another avian strategy for coping with high altitude.
Collapse
Affiliation(s)
- Sabine L Lague
- Department of Zoology, University of British Columbia, BC, Canada
| | | | - Julia M York
- Department of Zoology, University of British Columbia, BC, Canada
- Department of Integrative Biology, University of Texas at Austin, TX, USA
| | - Beverly A Chua
- Department of Zoology, University of British Columbia, BC, Canada
| | - Luis Alza
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, FL, USA
- Division of Ornithology, Centro de Ornitologia y Biodiversidad, Peru
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK, USA
| | - Rebecca Cheek
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK, USA
| | - Neal J Dawson
- Department of Biology, McMaster University, ON, Canada
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, FL, USA
| | - Peter B Frappell
- Institute for Marine and Antarctic Studies, University of Tasmania, Tasmania, Australia
| | | | - Kevin G McCracken
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, FL, USA
- Division of Ornithology, Centro de Ornitologia y Biodiversidad, Peru
- Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK, USA
| | | | - William K Milsom
- Department of Zoology, University of British Columbia, BC, Canada
| |
Collapse
|
17
|
Parr N, Wilkes M, Hawkes LA. Natural Climbers: Insights from Avian Physiology at High Altitude. High Alt Med Biol 2019; 20:427-437. [DOI: 10.1089/ham.2019.0032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Nicole Parr
- College of Life and Environmental Sciences, University of Exeter, Penryn Campus, Cornwall, United Kingdom
| | - Matt Wilkes
- Centre for Altitude Space and Extreme Environment Medicine, Institute of Sport, Exercise and Health, London, United Kingdom
| | - Lucy Alice Hawkes
- Hatherly Laboratories, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| |
Collapse
|
18
|
Storz JF, Scott GR. Life Ascending: Mechanism and Process in Physiological Adaptation to High-Altitude Hypoxia. ANNUAL REVIEW OF ECOLOGY EVOLUTION AND SYSTEMATICS 2019; 50:503-526. [PMID: 33033467 DOI: 10.1146/annurev-ecolsys-110218-025014] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
To cope with the reduced availability of O2 at high altitude, air-breathing vertebrates have evolved myriad adjustments in the cardiorespiratory system to match tissue O2 delivery with metabolic O2 demand. We explain how changes at interacting steps of the O2 transport pathway contribute to plastic and evolved changes in whole-animal aerobic performance under hypoxia. In vertebrates native to high altitude, enhancements of aerobic performance under hypoxia are attributable to a combination of environmentally induced and evolved changes in multiple steps of the pathway. Additionally, evidence suggests that many high-altitude natives have evolved mechanisms for attenuating maladaptive acclimatization responses to hypoxia, resulting in counter-gradient patterns of altitudinal variation for key physiological phenotypes. For traits that exhibit counteracting environmental and genetic effects, evolved changes in phenotype may be cryptic under field conditions and can only be revealed by rearing representatives of high-and low-altitude populations under standardized environmental conditions to control for plasticity.
Collapse
Affiliation(s)
- Jay F Storz
- School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588, USA
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4K1, Canada
| |
Collapse
|
19
|
Ivy CM, Lague SL, York JM, Chua BA, Alza L, Cheek R, Dawson NJ, Frappell PB, McCracken KG, Milsom WK, Scott GR. Control of breathing and respiratory gas exchange in high-altitude ducks native to the Andes. ACTA ACUST UNITED AC 2019; 222:jeb.198622. [PMID: 30846536 DOI: 10.1242/jeb.198622] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 03/03/2019] [Indexed: 11/20/2022]
Abstract
We examined the control of breathing and respiratory gas exchange in six species of high-altitude duck that independently colonized the high Andes. We compared ducks from high-altitude populations in Peru (Lake Titicaca at ∼3800 m above sea level; Chancay River at ∼3000-4100 m) with closely related populations or species from low altitude. Hypoxic ventilatory responses were measured shortly after capture at the native altitude. In general, ducks responded to acute hypoxia with robust increases in total ventilation and pulmonary O2 extraction. O2 consumption rates were maintained or increased slightly in acute hypoxia, despite ∼1-2°C reductions in body temperature in most species. Two high-altitude taxa - yellow-billed pintail and torrent duck - exhibited higher total ventilation than their low-altitude counterparts, and yellow-billed pintail exhibited greater increases in pulmonary O2 extraction in severe hypoxia. In contrast, three other high-altitude taxa - Andean ruddy duck, Andean cinnamon teal and speckled teal - had similar or slightly reduced total ventilation and pulmonary O2 extraction compared with low-altitude relatives. Arterial O2 saturation (S aO2 ) was elevated in yellow-billed pintails at moderate levels of hypoxia, but there were no differences in S aO2 in other high-altitude taxa compared with their close relatives. This finding suggests that improvements in S aO2 in hypoxia can require increases in both breathing and haemoglobin-O2 affinity, because the yellow-billed pintail was the only high-altitude duck with concurrent increases in both traits compared with its low-altitude relative. Overall, our results suggest that distinct physiological strategies for coping with hypoxia can exist across different high-altitude lineages, even among those inhabiting very similar high-altitude habitats.
Collapse
Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
| | - Sabine L Lague
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Julia M York
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4.,Department of Integrative Biology, University of Texas at Austin, TX 78712, USA
| | - Beverly A Chua
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Luis Alza
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA.,Division of Ornithology, Centro de Ornitologia y Biodiversidad, Lima 33, Peru.,Department of Biology and Wildlife, Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK 99755, USA
| | - Rebecca Cheek
- Department of Biology and Wildlife, Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK 99755, USA
| | - Neal J Dawson
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
| | - Peter B Frappell
- Zoology Department, Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania 7001, Australia
| | - Kevin G McCracken
- Department of Biology and Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, University of Miami, Coral Gables, FL 33146, USA.,Division of Ornithology, Centro de Ornitologia y Biodiversidad, Lima 33, Peru.,Department of Biology and Wildlife, Institute of Arctic Biology and University of Alaska Museum, University of Alaska Fairbanks, AK 99755, USA.,Human Genetics and Genomics, University of Miller School of Medicine, Miami, FL 33136, USA
| | - William K Milsom
- Department of Zoology, University of British Columbia, Vancouver, BC, Canada, V6T 1Z4
| | - Graham R Scott
- Department of Biology, McMaster University, Hamilton, ON, Canada, L8S 4K1
| |
Collapse
|
20
|
Convergent evolution on the hypoxia-inducible factor (HIF) pathway genes EGLN1 and EPAS1 in high-altitude ducks. Heredity (Edinb) 2019; 122:819-832. [PMID: 30631144 PMCID: PMC6781116 DOI: 10.1038/s41437-018-0173-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 12/04/2018] [Accepted: 12/05/2018] [Indexed: 12/15/2022] Open
Abstract
During periods of reduced O2 supply, the most profound changes in gene expression are mediated by hypoxia-inducible factor (HIF) transcription factors that play a key role in cellular responses to low-O2 tension. Using target-enrichment sequencing, we tested whether variation in 26 genes in the HIF signaling pathway was associated with high altitude and therefore corresponding O2 availability in three duck species that colonized the Andes from ancestral low-altitude habitats in South America. We found strong support for convergent evolution in the case of two of the three duck species with the same genes (EGLN1, EPAS1), and even the same exons (exon 12, EPAS1), exhibiting extreme outliers with a high probability of directional selection in the high-altitude populations. These results mirror patterns of adaptation seen in human populations, which showed mutations in EPAS1, and transcriptional regulation differences in EGLN1, causing changes in downstream target transactivation, associated with a blunted hypoxic response.
Collapse
|
21
|
Ivy CM, Scott GR. Evolved changes in breathing and CO 2 sensitivity in deer mice native to high altitudes. Am J Physiol Regul Integr Comp Physiol 2018; 315:R1027-R1037. [PMID: 30183337 DOI: 10.1152/ajpregu.00220.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
We examined the control of breathing by O2 and CO2 in deer mice native to high altitude to help uncover the physiological specializations used to cope with hypoxia in high-altitude environments. Highland deer mice ( Peromyscus maniculatus) and lowland white-footed mice ( P. leucopus) were bred in captivity at sea level. The first and second generation progeny of each population was raised to adulthood and then acclimated to normoxia or hypobaric hypoxia (12 kPa O2, simulating hypoxia at ~4,300 m) for 6-8 wk. Ventilatory responses to poikilocapnic hypoxia (stepwise reductions in inspired O2) and hypercapnia (stepwise increases in inspired CO2) were then compared between groups. Both generations of lowlanders appeared to exhibit ventilatory acclimatization to hypoxia (VAH), in which hypoxia acclimation enhanced the hypoxic ventilatory response and/or made the breathing pattern more effective (higher tidal volumes and lower breathing frequencies at a given total ventilation). In contrast, hypoxia acclimation had no effect on breathing in either generation of highlanders, and breathing was generally similar to hypoxia-acclimated lowlanders. Therefore, attenuation of VAH may be an evolved feature of highlanders that persists for multiple generations in captivity. Hypoxia acclimation increased CO2 sensitivity of breathing, but in this case, the effect of hypoxia acclimation was similar in highlanders and lowlanders. Our results suggest that highland deer mice have evolved high rates of alveolar ventilation that are unaltered by exposure to chronic hypoxia, but they have preserved ventilatory sensitivity to CO2.
Collapse
Affiliation(s)
- Catherine M Ivy
- Department of Biology, McMaster University , Hamilton, ON , Canada
| | - Graham R Scott
- Department of Biology, McMaster University , Hamilton, ON , Canada
| |
Collapse
|
22
|
Ivy CM, York JM, Lague SL, Chua BA, Alza L, McCracken KG, Milsom WK, Scott GR. Validation of a Pulse Oximetry System for High-Altitude Waterfowl by Examining the Hypoxia Responses of the Andean Goose (Chloephaga melanoptera). Physiol Biochem Zool 2018. [DOI: 10.1086/697053] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
23
|
York JM, Scadeng M, McCracken KG, Milsom WK. Respiratory mechanics and morphology of Tibetan and Andean high-altitude geese with divergent life histories. ACTA ACUST UNITED AC 2018; 221:jeb.170738. [PMID: 29180602 DOI: 10.1242/jeb.170738] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 11/21/2017] [Indexed: 12/31/2022]
Abstract
High-altitude bar-headed geese (Anser indicus) and Andean geese (Chloephaga melanoptera) have been shown to preferentially increase tidal volume over breathing frequency when increasing ventilation during exposure to hypoxia. Increasing tidal volume is a more effective breathing strategy but is also thought to be more mechanically and metabolically expensive. We asked whether there might be differences in the mechanics or morphology of the respiratory systems of high-altitude transient bar-headed geese and high-altitude resident Andean geese that could minimize the cost of breathing more deeply. We compared these two species with a low-altitude migratory species, the barnacle goose (Branta leucopsis). We ventilated anesthetized birds to measure mechanical properties of the respiratory system and used CT scans to quantify respiratory morphology. We found that the respiratory system of Andean geese was disproportionately larger than that of the other two species, allowing use of a deeper breathing strategy for the same energetic cost. The relative size of the respiratory system, especially the caudal air sacs, of bar-headed geese was also larger than that of barnacle geese. However, when normalized to respiratory system size, the mechanical cost of breathing did not differ significantly among these three species, indicating that deeper breathing is enabled by morphological but not mechanical differences between species. The metabolic cost of breathing was estimated to be <1% of basal metabolic rate at rest in normoxia. Because of differences in the magnitude of the ventilatory response, the cost of breathing was estimated to increase 7- to 10-fold in bar-headed and barnacle geese in severe hypoxia, but less than 1-fold in Andean geese exposed to the same low atmospheric PO2.
Collapse
Affiliation(s)
- Julia M York
- University of British Columbia, Department of Zoology, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| | - Miriam Scadeng
- University of California San Diego, Department of Radiology, Center for Functional MRI, 9500 Gilman Drive 0677, La Jolla, CA, USA 92093
| | - Kevin G McCracken
- University of Miami, Department of Biology, Department of Marine Biology and Ecology, Rosenstiel School of Marine and Atmospheric Sciences, and Human Genetics and Genomics - Miller School of Medicine, Coral Gables, FL, 33146, USA
| | - William K Milsom
- University of British Columbia, Department of Zoology, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4
| |
Collapse
|
24
|
Knight K. Andean and Tibetan birds crack breathing in different ways. J Exp Biol 2017. [DOI: 10.1242/jeb.172361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
25
|
Laguë SL. High-altitude champions: birds that live and migrate at altitude. J Appl Physiol (1985) 2017; 123:942-950. [PMID: 28839002 DOI: 10.1152/japplphysiol.00110.2017] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 08/09/2017] [Accepted: 08/14/2017] [Indexed: 11/22/2022] Open
Abstract
High altitude is physiologically challenging for vertebrate life for many reasons, including hypoxia (low environmental oxygen); yet, many birds thrive at altitude. Compared with mammals, birds have additional enhancements to their oxygen transport cascade, the conceptual series of steps responsible for acquiring oxygen from the environment and transporting it to the mitochondria. These adaptations have allowed them to inhabit a number of high-altitude regions. Waterfowl are a taxon prolific at altitude. This minireview explores the physiological responses of high-altitude waterfowl (geese and ducks), comparing the strategies of lifelong high-altitude residents to those of transient high-altitude performers, providing insight into how birds champion high-altitude life. In particular, this review highlights and contrasts the physiological hypoxia responses of bar-headed geese (Anser indicus), birds that migrate biannually through the Himalayas (4,500-6,500 m), and Andean geese (Chloephaga melanoptera), lifelong residents of the Andes (4,000-5,500 m). These two species exhibit markedly different ventilatory and cardiovascular strategies for coping with hypoxia: bar-headed geese robustly increase convective oxygen transport elements (i.e., heart rate and total ventilation) whereas Andean geese rely predominantly on enhancements that are likely morphological in origin (i.e., increases in lung oxygen diffusion and cardiac stroke volume). The minireview compares the short- and long-term cardiovascular and ventilatory trade-offs of these different physiological strategies and offers hypotheses surrounding their origins. It also draws parallels to high-altitude human physiology and research, and identifies a number of areas of further research. The field of high-altitude avian physiology offers a unique and broadly applicable insight into physiological enhancements in hypoxia.
Collapse
|