Thrifty phenotype versus cold adaptation: trade-offs in upper limb proportions of Himalayan populations of Nepal

The multi-stress environment of high altitude has been associated with growth deficits in humans, particularly in zeugopod elements (forearm and lower leg). This is consistent with the thrifty phenotype hypothesis, which has been observed in Andeans, but has yet to be tested in other high-altitude populations. In Himalayan populations, other factors, such as cold stress, may shape limb proportions. The current study investigated whether relative upper limb proportions of Himalayan adults ( n = 254) differ between highland and lowland populations, and whether cold adaptation or a thrifty phenotype mechanism may be acting here. Height, weight, humerus length, ulna length, hand length and hand width were measured using standard methods. Relative to height, total upper limb and ulna lengths were significantly shorter in highlanders compared with lowlanders in both sexes, while hand and humerus length were not. Hand width did not significantly differ between populations. These results support the thrifty phenotype hypothesis, as hand and humerus proportions are conserved at the expense of the ulna. The reduction in relative ulna length could be attributed to cold adaptation, but the lack of difference between populations in both hand length and width indicates that cold adaptation is not shaping hand proportions in this case.

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Trade-Offs in Relative Limb Length among Peruvian Children: Extending the Thrifty Phenotype Hypothesis to Limb Proportions

PLoS ONE ◽

10.1371/journal.pone.0051795 ◽

2012 ◽

Vol 7 (12) ◽

pp. e51795 ◽

Cited By ~ 63

Author(s):

Emma Pomeroy ◽

Jay T. Stock ◽

Sanja Stanojevic ◽

J. Jaime Miranda ◽

Tim J. Cole ◽

...

Keyword(s):

Limb Length ◽

Thrifty Phenotype ◽

Thrifty Phenotype Hypothesis ◽

Trade Offs ◽

Limb Proportions

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Evolution of nonspectral rhodopsin function at high altitudes

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1705765114 ◽

2017 ◽

Vol 114 (28) ◽

pp. 7385-7390 ◽

Cited By ~ 13

Author(s):

Gianni M. Castiglione ◽

Frances E. Hauser ◽

Brian S. Liao ◽

Nathan K. Lujan ◽

Alexander Van Nynatten ◽

...

Keyword(s):

High Altitude ◽

Cold Adaptation ◽

Natural Variation ◽

Thermal Adaptation ◽

Intramolecular Hydrogen Bonding ◽

Site Directed Mutagenesis ◽

Temperature Sensitive ◽

Cold Temperatures ◽

Trade Offs ◽

Intramolecular Hydrogen

High-altitude environments present a range of biochemical and physiological challenges for organisms through decreases in oxygen, pressure, and temperature relative to lowland habitats. Protein-level adaptations to hypoxic high-altitude conditions have been identified in multiple terrestrial endotherms; however, comparable adaptations in aquatic ectotherms, such as fishes, have not been as extensively characterized. In enzyme proteins, cold adaptation is attained through functional trade-offs between stability and activity, often mediated by substitutions outside the active site. Little is known whether signaling proteins [e.g., G protein-coupled receptors (GPCRs)] exhibit natural variation in response to cold temperatures. Rhodopsin (RH1), the temperature-sensitive visual pigment mediating dim-light vision, offers an opportunity to enhance our understanding of thermal adaptation in a model GPCR. Here, we investigate the evolution of rhodopsin function in an Andean mountain catfish system spanning a range of elevations. Using molecular evolutionary analyses and site-directed mutagenesis experiments, we provide evidence for cold adaptation in RH1. We find that unique amino acid substitutions occur at sites under positive selection in high-altitude catfishes, located at opposite ends of the RH1 intramolecular hydrogen-bonding network. Natural high-altitude variants introduced into these sites via mutagenesis have limited effects on spectral tuning, yet decrease the stability of dark-state and light-activated rhodopsin, accelerating the decay of ligand-bound forms. As found in cold-adapted enzymes, this phenotype likely compensates for a cold-induced decrease in kinetic rates—properties of rhodopsin that mediate rod sensitivity and visual performance. Our results support a role for natural variation in enhancing the performance of GPCRs in response to cold temperatures.

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Strategies and adaptations to aquatic life at high altitude

10.1093/oso/9780198736868.003.0005 ◽

2017 ◽

Author(s):

Dean Jacobsen ◽

Olivier Dangles

Keyword(s):

High Altitude ◽

Environmental Conditions ◽

Low Temperatures ◽

Cold Adaptation ◽

Inorganic Carbon ◽

Direct Result ◽

Aquatic Life ◽

Dissolved Carbon ◽

Dissolved Carbon Dioxide ◽

Regulatory Capacity

Chapter 5 is focused on how organisms cope with the environmental conditions that are a direct result of high altitude. Organisms reveal a number of fascinating ways of dealing with a life at high altitude; for example, avoidance and pigmentation as protection against damaging high levels of ultraviolet radiation, accumulation of antifreeze proteins, and metabolic cold adaptation among species encountering low temperatures with the risk of freezing, oxy-regulatory capacity in animals due to low availability of oxygen, and root uptake from the sediment of inorganic carbon by plants living in waters poor in dissolved carbon dioxide. These and more adaptations are carefully described through a number of examples from famous flagship species in addition to the less well-known ones. Harsh environmental conditions work as an environmental filter that only allows the well-adapted species to slip through to colonize high altitude waters.

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The Shoulders and Arms of Sunghir 1 to 3

The People of Sunghir ◽

10.1093/oso/9780199381050.003.0015 ◽

2014 ◽

Author(s):

Erik Trinkaus ◽

Alexandra P. Buzhilova ◽

Maria B. Mednikova ◽

Maria V. Dobrovolskaya

Keyword(s):

Upper Limb ◽

Coracoid Process ◽

Left Forearm ◽

Left Hand ◽

Forearm Bones ◽

Limb Asymmetry ◽

Human Upper Limb ◽

Left Humerus ◽

Limb Proportions

The three partial skeletons from Sunghir retain substantial portions of their shoulder and arm remains, from the proximal clavicle to the distal radius and ulna. The scapulae, as with most of those from the Pleistocene, retain principally the spine, the glenoid area, the coracoid process, and the axillary border. The left forearm of Sunghir 2 is absent (as is his left hand), and the left humerus consists of a diaphyseal section without the metaphyses and a partial proximal epiphysis. It is nonetheless possible to assess both overall upper limb proportions (chapter 11) and a number of aspects that relate to upper limb asymmetry, clavicle and scapular morphology, glenohumeral proportions, diaphyseal robustness, cubital articulations, and reflections of pronation-supination hypertrophy for all three of them. Although humans are considered to be bilaterally symmetrical in their limbs, there are small degrees of asymmetry in most limb bones. These asymmetries are frequently exaggerated in the human upper limb, given our handedness and the subsequent preference for use of the dominant arm in more mechanically demanding activities (Raymond and Pontier 2004). In general, the level of asymmetry in the dimensions of epiphyses, and especially of articulations, is modest. However, substantial asymmetry in measures of upper limb diaphyses (particularly of the humerus) have been documented in samples of recent humans (e.g., Ruff and Jones 1981; Fresia et al. 1990; Trinkaus et al. 1994; Roy et al. 1994; Churchill 1994; Steele and Mays 1995; Sakaue 1997; Mays 2002; Auerbach and Ruff 2006; Cowgill 2008; Auerbach and Raxter 2008), as well as in a number of Late Pleistocene humans (e.g., Trinkaus et al. 1994; Churchill and Formicola 1997; Cowgill 2008; Shang and Trinkaus 2010; Cowgill et al. 2012b; Mednikova 2012; Volpato et al. 2012). Moreover, as is indicated by labial anterior dental striations and one individual’s forearm bones, such handedness extends back through the genus Homo (Weaver et al. 2001; Frayer et al. 2012).

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Recharacterizing the Metabolic State of Energy Balance in Thrifty and Spendthrift Phenotypes

The Journal of Clinical Endocrinology & Metabolism ◽

10.1210/clinem/dgaa098 ◽

2020 ◽

Vol 105 (5) ◽

pp. 1375-1392 ◽

Cited By ~ 2

Author(s):

Tim Hollstein ◽

Alessio Basolo ◽

Takafumi Ando ◽

Susanne B Votruba ◽

Mary Walter ◽

...

Keyword(s):

Energy Balance ◽

Healthy Subjects ◽

Liquid Chromatography Mass Spectrometry ◽

Short Term ◽

Urinary Catecholamines ◽

Metabolic Phenotypes ◽

Thrifty Phenotype ◽

Thrifty Phenotype Hypothesis ◽

The Difference ◽

Prevailing View

Abstract Purpose The human thrifty phenotype hypothesis presupposes that lower 24-hour (24h) energy expenditure (24EE) during famine preserves body mass and promotes survival. The prevailing view defines thrifty individuals as having a lower 24EE during fasting. However, it is also plausible that the greater decline in 24EE during fasting in thrifty individuals is due to higher 24EE during energy balance conditions (ENBAL). Herein, we provide evidence that this is indeed the case. Methods In 108 healthy subjects, 24EE was measured in a whole-room indirect calorimeter both during ENBAL and 24h fasting conditions. Subjects were categorized as thrifty or spendthrift based on the median value (−162 kcal/day) of the difference in 24EE (adjusted for body composition) between fasting and ENBAL conditions. Concomitant 24h urinary catecholamines were assessed by liquid chromatography–mass spectrometry. Results Compared to ENBAL, 24EE decreased during 24h fasting by 172 kcal/day (standard deviation = 93; range, −470 to 122). A greater-than-median decrease in 24EE (“thriftier” phenotype) was due to higher 24EE during ENBAL (+124 kcal/day; P < 0.0001) but not to lower 24EE during fasting (P = 0.35). Greater fasting-induced increase in epinephrine was associated with concomitant lower decrease in 24EE (r = 0.27; P = 0.006). Main Conclusion The greater decrease in 24EE during acute fasting (which characterizes the thrifty phenotype) is not due to reduced metabolic rate during fasting but to a relatively higher 24EE during feeding conditions, and this decrease in 24EE during fasting is accompanied by a smaller increase in epinephrine. These results recharacterize the prevailing view of the short-term 24EE responses that define the human metabolic phenotypes. Clinical Trials: NCT00523627, NCT00687115, NCT02939404

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