High altitude phenotype

Figure 5.6. A diagrammatic summary of adjusted hypoxia response systems (the AHRS) proposed as the ancestral physiological phenotype and as a phylogenetic adaptation to hypobaric hypoxia. Summary based largely upon studies of Quechuas and Sherpas. Essentially all of the characteristics summarized here are also expressed in individuals well adapted for endurance performance. In the latter, the main modification involves an upwards regulation of mitochondrial volume densities at the working tissues (altered expression of mitochondrial metabolic enzymes and metabolite transporters above), which is why this is referred to as a high-capacity version of the lower capacity high-altitude phenotype. See text for further details. (Modified from Hochachka et al., 1999.)...

ADAPTABLE TRAITS AND A HIGH-ALTITUDE PHYSIOLOGICAL PHENOTYPE... 

Ancestral phenotype used in defense against hypoxia for endurance in high altitude groups... 

---