Revealing hidden genetic variability in unfavourable conditions

Several mechanisms are active in a number of organisms, including multicellular animals and plants, that enable them to accelerate evolution when they find themselves in unfavourable circumstances. In some cases, heat shock proteins (Hsp) are of key importance; this is apparently primarily HSP90 in metazoa (Rutherford & Lindquist 1998; Rutherford 2000; Rutherford 2003). Heat shock proteins allow folding of newly synthesized (linear) proteins into the correct spatial shape and can also “repair” proteins, whose shape was damaged by external effects, such as a thermal shock. The activity of some Hsp is of key importance, especially for proteins, whose primary structure is already affected by the mutations present. Under normal circumstances, Hsp are apparently capable of neutralizing the effect of a substantial percentage of these mutations and are able to ensure that a great many abnormal proteins form a normal and completely functional tertiary structure – a three-dimensional shape. If the organism finds itself under abnormal conditions, the Hsp are mobilized for other functions and there begins to be an acute lack of them in the cell. In this case, the presence of the already present mutations begins to be manifested in the tertiary structure of the proteins and subsequently in the phenotype of the organisms. Thus, under abnormally unfavourable conditions, so far unrevealed genetic variability begins to be manifested in the phenotype of the individual organisms in the population and this variability can become material for natural selection and thus also for adaptive evolutionary changes. Populations and species can thus react rapidly to drastic changes in their environments.

Was this information useful for you?
The classical Darwinian theory of evolution can explain the evolution of adaptive traits only in asexual organisms. The frozen plasticity theory is much more general: It can also explain the origin and evolution of adaptive traits in both asexual and sexual organisms Read more