Limits on Inferring Genetic Adaptation to High Altitude in Himalayan and Andean Populations

Brutsaert, Tom D.

doi:10.1089/152702901750265314

Cited by 18 publications

(10 citation statements)

References 90 publications

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“…The rationale for this particular design is that traits that do not deacclimate may represent historically fixed traits in the population. This does not necessarily need to be the case because of irreversible developmental effects (Brutsaert, 2001), but nevertheless the present study has replicated this aspect of the Hochachaka et al study. Again, the present study shows no efficiency differences between highland Aymara (group 1), deacclimatized Aymara who have been in the lowlands for at least 2 months (group 6), and Aymara who have been born and raised in the lowlands (group 8).…”

supporting

confidence: 77%

Absence of Work Efficiency Differences During Cycle Ergometry Exercise in Bolivian Aymara

Brutsaert

Haas

Spielvogel

2004

High Altitude Medicine & Biology

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This study tested the hypothesis that Andean natives are adapted to high altitude (HA) via high work efficiency during exercise in hypoxia. A total of 186 young males and females were tested in Bolivia, comprising eight different subject groups. Groups were identified based on gender, ancestry (Aymara vs. European), altitude of birth (highlands vs. lowlands), and the altitude where tested (420, 3600, 3850 m). This design allows partitioning of ancestral (i.e., genetic) and developmental effects. To minimize measurement error, subjects were given two submaximal exercise tests on a cycle ergometer (on separate days). Each test consisted of four 5-min work bouts (levels), each separated by a 5-min rest period. For all groups, the oxygen consumption (V(O2))-work rate relationship was not different from the sea-level reference. Gross and net efficiencies (GE and NE) were not different between groups at any work level, with the exception of European men born in the lowlands and acclimatized and tested at 3600 m. These men showed slightly lower V(O2) at high work output, but this may be due to a nonsteady-state V(O2) kinetic, rather than to an altered steady-state V(O2)-work rate relationship per se. There were no significant group differences in delta efficiency (DE). In sum, these results provide no support for the hypothesis of energetic advantage during submaximal work in Andean HA natives. A review and analysis of the literature suggest that the same is true for HA natives in the Himalayas.

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supporting

confidence: 77%

Absence of Work Efficiency Differences During Cycle Ergometry Exercise in Bolivian Aymara

Brutsaert

Haas

Spielvogel

2004

High Altitude Medicine & Biology

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“…The statistical interaction between birthplace and ADMIX can be interpreted as the effect of genes, depending on lifelong exposure to HA. The inference of gene‐environment interaction would depend on whether highland‐ and lowland‐born groups were well‐matched, and on whether environmental effects were controlled, including acclimatization state and maternal effects (Brutsaert, 2001). Interestingly, a nonsignificant trend for this type of interaction was detected between birthplace and ADMIX on SpO 2 ( P < 0.1, model 9, Table 4).…”

Section: Discussionmentioning

confidence: 99%

Effects of birthplace and individual genetic admixture on lung volume and exercise phenotypes of Peruvian Quechua

Brutsaert

Parra

Shriver

et al. 2003

American J Phys Anthropol

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Forced vital capacity (FVC) and maximal exercise response were measured in two populations of Peruvian males (age, 18-35 years) at 4,338 m who differed by the environment in which they were born and raised, i.e., high altitude (Cerro de Pasco, Peru, BHA, n = 39) and sea level (Lima, Peru, BSL, n = 32). BSL subjects were transported from sea level to 4,338 m, and were evaluated within 24 hr of exposure to hypobaric hypoxia. Individual admixture level (ADMIX, % Spanish ancestry) was estimated for each subject, using 22 ancestry-informative genetic markers and also by skin reflectance measurement (MEL). Birthplace accounted for the approximately 10% larger FVC (P < 0.001), approximately 15% higher maximal oxygen consumption (VO(2)max, ml.min(-1).kg(-1)) (P < 0.001), and approximately 5% higher arterial oxygen saturation during exercise (SpO(2)) (P < 0.001) of BHA subjects. ADMIX was low in both study groups, averaging 9.5 +/- 2.6% and 2.1 +/- 0.3% in BSL and BHA subjects, respectively. Mean underarm MEL was significantly higher in the BSL group (P < 0.001), despite higher ADMIX. ADMIX was not associated with any study phenotype, but study power was not sufficient to evaluate hypotheses of genetic adaptation via the ADMIX variable. MEL and FVC were positively correlated in the BHA (P = 0.035) but not BSL (P = 0.335) subjects. However, MEL and ADMIX were not correlated across the entire study sample (P = 0.282). In summary, results from this study emphasize the importance of developmental adaptation to high altitude. While the MEL-FVC correlation may reflect genetic adaptation to high altitude, study results suggest that alternate (environmental) explanations be considered.

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“…Therefore, the linguistic origin of a participant's parents' surnames (giving 4 surnames for analysis) can be used to infer the proportion of indigenous ancestry of that individual. While an imperfect marker (Brutsaert, ; Greksa, ), this approach has been used successfully in numerous studies of Andean populations that have aimed to relate birth characteristics to ancestry (Bennett et al, ; Gonzales et al, ; Julian et al, ; Mueller et al, ; Soria et al, ) and the association between native ancestry and surname origin in the Andes has been previously validated (Chakraborty et al, ). The four parental surnames of each individual were classified as “indigenous,” “mestizo,” (mixed) or “foreign” based on their linguistic origin using a surname dictionary complied by one of the authors (LGM).…”

Section: Methodsmentioning

confidence: 99%

Surname‐Inferred andean ancestry is associated with child stature and limb lengths at high altitude in Peru, but not at sea level

Pomeroy

Wells

Stanojevic

et al. 2015

American J Hum Biol

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ObjectivesNative Andean ancestry gives partial protection from reduced birthweight at high altitude in the Andes compared with European ancestry. Whether Andean ancestry is also associated with body proportions and greater postnatal body size at altitude is unknown. Therefore, we tested whether a greater proportion of Andean ancestry is associated with stature and body proportions among Peruvian children at high and low altitude.MethodsHeight, head circumference, head‐trunk height, upper and lower limb lengths, and tibia, ulna, hand and foot lengths, were measured in 133 highland and 169 lowland children aged 6 months to 8.5 years. For highland and lowland groups separately, age‐sex‐adjusted anthropometry z scores were regressed on the number of indigenous parental surnames as a proxy for Andean ancestry, adjusting for potential confounders (maternal age and education, parity, altitude [highlands only]).ResultsAmong highland children, greater Andean ancestry was negatively associated with stature and tibia, ulna, and lower limb lengths, independent of negative associations with greater altitude for these measurements. Relationships were strongest for tibia length: each additional Andean surname or 1,000 m increase at altitude among highland children was associated with 0.18 and 0.65 z score decreases in tibia length, respectively. Anthropometry was not significantly associated with ancestry among lowland children.ConclusionsGreater Andean ancestry is associated with shorter stature and limb measurements at high but not low altitude. Gene‐environment interactions between high altitude and Andean ancestry may exacerbate the trade‐off between chest dimensions and stature that was proposed previously, though we could not test this directly. Am. J. Hum. Biol. 27:798–806, 2015. © 2015 The Authors American Journal of Human Biology Published by Wiley Periodicals, Inc.

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Limits on Inferring Genetic Adaptation to High Altitude in Himalayan and Andean Populations

Cited by 18 publications

References 90 publications

Absence of Work Efficiency Differences During Cycle Ergometry Exercise in Bolivian Aymara

Absence of Work Efficiency Differences During Cycle Ergometry Exercise in Bolivian Aymara

Effects of birthplace and individual genetic admixture on lung volume and exercise phenotypes of Peruvian Quechua

Surname‐Inferred andean ancestry is associated with child stature and limb lengths at high altitude in Peru, but not at sea level

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