Evolution of muscle phenotype for extreme high altitude flight in the bar-headed goose

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Evolution of muscle phenotype for extreme high altitude flight in the bar-headed goose. / Scott, GR; Egginton, Stuart; Richards, JG; Milsom, WK.

In: Royal Society of London. Proceedings B. Biological Sciences, Vol. 276, No. 1673, 01.10.2009, p. 3645-3653.

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@article{40e25b8b8e46465da3004fccb0bb4f69,
title = "Evolution of muscle phenotype for extreme high altitude flight in the bar-headed goose",
abstract = "Bar-headed geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed geese with that of low altitude birds (barnacle geese, pink-footed geese, greylag geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O-2 diffusion capacity from the blood and reduce intracellular O-2 diffusion distances, respectively. The unique differences in bar-headed geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O-2 kinetics and phosphorylation efficiencies across species. Bar-headed geese have therefore evolved for exercise in hypoxia by enhancing the O-2 supply to flight muscle.",
keywords = "exercise performance, oxygen transport cascade, phylogenetically independent contrasts, high altitude adaptation, physiological evolution",
author = "GR Scott and Stuart Egginton and JG Richards and WK Milsom",
year = "2009",
month = oct,
day = "1",
doi = "10.1098/rspb.2009.0947",
language = "English",
volume = "276",
pages = "3645--3653",
journal = "Royal Society of London. Proceedings B. Biological Sciences",
issn = "0962-8452",
publisher = "The Royal Society",
number = "1673",

}

RIS

TY - JOUR

T1 - Evolution of muscle phenotype for extreme high altitude flight in the bar-headed goose

AU - Scott, GR

AU - Egginton, Stuart

AU - Richards, JG

AU - Milsom, WK

PY - 2009/10/1

Y1 - 2009/10/1

N2 - Bar-headed geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed geese with that of low altitude birds (barnacle geese, pink-footed geese, greylag geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O-2 diffusion capacity from the blood and reduce intracellular O-2 diffusion distances, respectively. The unique differences in bar-headed geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O-2 kinetics and phosphorylation efficiencies across species. Bar-headed geese have therefore evolved for exercise in hypoxia by enhancing the O-2 supply to flight muscle.

AB - Bar-headed geese migrate over the Himalayas at up to 9000 m elevation, but it is unclear how they sustain the high metabolic rates needed for flight in the severe hypoxia at these altitudes. To better understand the basis for this physiological feat, we compared the flight muscle phenotype of bar-headed geese with that of low altitude birds (barnacle geese, pink-footed geese, greylag geese and mallard ducks). Bar-headed goose muscle had a higher proportion of oxidative fibres. This increased muscle aerobic capacity, because the mitochondrial volume densities of each fibre type were similar between species. However, bar-headed geese had more capillaries per muscle fibre than expected from this increase in aerobic capacity, as well as higher capillary densities and more homogeneous capillary spacing. Their mitochondria were also redistributed towards the subsarcolemma (cell membrane) and adjacent to capillaries. These alterations should improve O-2 diffusion capacity from the blood and reduce intracellular O-2 diffusion distances, respectively. The unique differences in bar-headed geese were much greater than the minor variation between low altitude species and existed without prior exercise or hypoxia exposure, and the correlation of these traits to flight altitude was independent of phylogeny. In contrast, isolated mitochondria had similar respiratory capacities, O-2 kinetics and phosphorylation efficiencies across species. Bar-headed geese have therefore evolved for exercise in hypoxia by enhancing the O-2 supply to flight muscle.

KW - exercise performance

KW - oxygen transport cascade

KW - phylogenetically independent contrasts

KW - high altitude adaptation

KW - physiological evolution

U2 - 10.1098/rspb.2009.0947

DO - 10.1098/rspb.2009.0947

M3 - Article

C2 - 19640884

VL - 276

SP - 3645

EP - 3653

JO - Royal Society of London. Proceedings B. Biological Sciences

JF - Royal Society of London. Proceedings B. Biological Sciences

SN - 0962-8452

IS - 1673

ER -