Study
Two routes to functional adaptation: Tibetan and Andean high-altitude natives
Beall, Cynthia M.
Proceedings of the National Academy of Sciences, 2007
Compared oxygen transport physiology between long-resident Tibetan and Andean highland populations at comparable altitudes, measuring haemoglobin concentration, oxygen saturation, ventilation and nitric oxide.
- Studied in
- Homo sapiens
- Sample size
- population comparison across two highland regions
The two populations solve the same problem differently. Andean highlanders carry markedly elevated haemoglobin; Tibetans do not, instead breathing faster and maintaining much higher nitric oxide with greater blood flow.
What it means
The authors' reading, and ours. Where they differ, that difference is the point.
How the authors put it
There is more than one adaptive solution to chronic hypoxia, and the two populations reached different ones over different lengths of residence.
How NatureHQ reads it
The record that makes adaptation legible as something other than a single inevitable answer. It also separates cleanly from acclimatisation: the visiting lowlander does the Andean thing, badly and reversibly, and the Tibetan solution is not available to them at all.
- Population comparisons cannot fully separate genetic difference from lifelong developmental exposure.
- Both populations are heterogeneous, and within-population variation is substantial.
What this study is used for on NatureHQ
One study can inform several subjects. Here is everywhere this one is cited.
Published by: Proceedings of the National Academy of SciencesPublished in PNAS.
doi.org/10.1073/pnas.0701985104
Checked against Crossref on 2026-09-28, and they agree on the title, the authors and the year.
NatureHQ summarises research in its own words and does not reproduce published text. Reviewed 2026-09-03.