Adaptive Phenotypes: Their Material Bases, Criteria and Proofs: A Review

The term adaptation is used to refer to a feature of structure, function, or behavior that is beneficial and enables survival in a specific environment. Most often, they talk about genetic adaptation. There is no generally accepted definition of adaptive phenotype (AP). Since natural selection "sees" only AP, and not a gene or genotype, there is a need to clarify existing concepts. It seems that the time has come to determine objective criteria that would allow to decide which morphological, physiological or behavioral trait to take for AP. Criteria are proposed on the basis of which it would be possible to decide whether this trait meets the requirements for AP. Genomics studies for high-altitude populations have identified 169 genes that the authors believe are under positive natural selection. However, they did not help to find a high-altitude AP that would be "visible" to natural selection. The issues concerning the material bases, criteria and methods of proving AP on the example of human adaptation to a high-altitude climate are discussed.