Tibetans (Genetics)
Tibetans show positive selection in EPAS1. Able to produce fewer RBCs. More RBCs = blood isn't able to pass through capillaries to get sufficient oxygen. I.e. less RBS = sufficient regulation of oxygen. Also have higher breathing rates and blood vessels that expand for better oxygen transport. All likely to contribute to adaptation.
Scientists found that these genes were found at a higher frequency than in their close relatives = rapid selection - the genes had a high rate of selection. Tibetans with these genes were favored as they began living in high altitudes = rapid selection.
Phenotypic plasticity vs. Adaptation
Lowlanders visiting high altitudes = plasticity. Bodies produce MORE RBCs help transport available oxygen in body to compensate for decreased oxygen levels.
Beall, C. M. Cavalleri, G. L., Deng, L., Elston, R. C., Gao, Y., Knight, J., . . . Zhang, Y. T. (2010). Natural selection on EPAS1 (HIF2a) associated with low hemoglobin concentration in Tibetan highlanders. Proceedings of the National Academy of Sciences USA 107: 11459-11464.
Yi, X., Liang, Y., Huerta-Sanchez, E., Jin, X., Cuo, Z. X. P., Pool, J. E. . . .Wang, J. (2010). Sequencing of 50 human exomes reveals adaptation to high altitude. Science 329: 75-78.
For Ethiopian evolution, Huerta-Sanchez identified BHLHE41, a gene involved in hypoxia and circadian rhythm pathways. It physically interacts with HIF-1a and represses many hypoxia-induced transcriptional targets.
Also, the Wiki page currently says Ethiopians live at above 3,000m, but I've been reading that it's mostly 2,500 which is lower than the Andean and Tibetan populations so that's another possible edit?
Huerta-Sanchez, M. et al. 2013. Genetic Signatures Reveal High-Altitude Adaptation in a Set of Ethiopian Populations. Strafingfire (talk) 21:08, 2 March 2016 (UTC)
- Different ways your body restores arterial oxygen content:
1. cardiovascular responses which increase cardiac output
2. alveolar gases exchange, kidney, and CNS responses to change the oxygen and carbon dioxide partial pressures
3. increased hemoglobin concentration
High-altitude environments are challenging for long term human habitation due to various environmental stressors, such as low barometric O2 pressure, low temperature and high UV radiation HugzApenguin (talk) 16:31, 8 March 2016 (UTC)
Evolution - Ethiopians/Andeans evolution Secondary - Adaptive genetic changes related to haemoglobin concentration in native high-altitude Tibetans (Simonson et al. 2015) - a review article that summarizes a lot of the recent literature already in the Wiki entry unfortunately
Primary - Whole genome sequencing of Ethiopian highlands reveals conserved hypoxia tolerance genes (Udpa et al. 2014) - Wiki entry doesn’t have this cited, but it does have the Andean counterpart, looks promising
Primary - Genetic signatures reveal high-altitude adaptation in a set of Ethiopian populations (Huerta-Sanchez et al. 2013) - More genes from Ethiopian populations, more data supporting convergent evolution in the hypoxia pathway
Huerta-Sanchez et al. 2013 talks about BHLHE41, which isn't in the Wiki page so there's something there maybe? Strafingfire (talk) 23:04, 28 February 2016 (UTC)
Plant adaptation
Alpine plant species may attain relatively greater carbon gains in abundant CO2 atmosphere than lowland plant species- able to efficiently uptake CO2 — Preceding unsigned comment added by Maple1005 (talk • contribs) 16:42, 8 March 2016 (UTC) [1]