Premium
Highland Andean Populations Show Reduced Variation in the Hypoxic Ventilatory Response
Author(s) -
Heinrich Erica C.,
Gaio Eduardo,
Powell Frank L.,
Macarlupú José Luis,
AnzaRamirez Cecilia,
Corante Noemi,
VizcardoGalindo Gustavo,
Villafuerte Francisco C.,
Simonson Tatum S.
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1007.8
Subject(s) - hypoxic ventilatory response , biology , acclimatization , hypoxia (environmental) , altitude (triangle) , effects of high altitude on humans , population , genetic variation , physiology , evolutionary biology , respiration , ecology , genetics , gene , demography , oxygen , botany , anatomy , chemistry , geometry , mathematics , organic chemistry , sociology
Multiple adaptive phenotypes for high‐altitude and hypoxic stress have developed by distinct evolutionary trajectories in highland populations. For example, considerable variation is observed in the hypoxic ventilatory response (HVR) of Tibetans, while high altitude Andean populations show blunted responses and low variation in this trait. Evidence suggests that genetic background plays a major role in these adaptations as native highlanders exhibit adaptive signals in genomic regions containing genes related to the hypoxic response. In some cases these signals are associated with physiological differences, such as hemoglobin concentration in Tibetans, which is relatively lower than levels observed in Andeans. Few adaptive signals have been reported in more than one highland population. This suggests distinct genetic contributions to different adaptive processes in these groups. We aim to link additional hypoxia‐related phenotypes to their underlying genetic basis in order to understand how different populations have adapted to life at high altitude. The present studies examine how ventilatory control and oxygen delivery differ in high altitude Andean populations compared to lowlanders. We measured the HVR in 50 lifelong male residents of Cerro de Pasco (CDP) (4,330 m) and compared to 15 sea‐level residents tested at UC San Diego (SL) and after acclimatization at 3,800 m (HA). Andean hemoglobin values ranged from 15.2 to 27.5 g/dL (20.1 ± 2.9 g/dL, M ± SD ). Consistent with previous reports, CDP residents have similar ventilation in normoxia compared to HA (CDP: 0.21 ± 0.06, HA: 0.19 ± 0.08 L·min −1 ·kg −1 , t (62)=1.54, p =0.22) CDP residents also demonstrate a blunted HVR with less variability than observed in SL or HA (CDP: 0.002 ± 0.005, SL: 0.008 ± 0.009, HA: 0.020 ±0.013 L·min −1 ·kg −1 ·% −1 , F (2, 77)=33.256, p <<0.001). Although CDP showed essentially no increase in ventilation in acute hypoxia, it is possible that oxygen delivery may increase with cardiac output, as evidenced by the expected increase in heart rate in isocapnic hypoxia ( F (5,290) = 12.54, p << 0.001). CDP also consistently maintain lower end‐tidal CO 2 values (26.93 ± 4.13 torr) compared to SL (34.99 ± 2.25 torr), as expected for acclimatization to high altitude, and also lower than HA (30.07 ± 2.58 torr) ( F (2, 77)=29.68, p<<0.001 ), as expected for acclimatization to a lower altitude. Using DNA samples collected from CDP, we will test if allelic variation in candidate genes previously identified to be involved in the hypoxic response (and under selection in high‐altitude populations) explains any of the variation in these physiological variables. Support or Funding Information This work was supported by NIH grant T32HL098062 to FLP.