XII. The antagonistic pleiotropy theory sees the cause of ageing in evolutionary fixation of alleles that enhance the viability of young individuals while reducing the viability of old individuals

The antagonistic pleiotropy theory goes even further.This theory assumes that a great many mutations have pleiotropic effect, i.e. that they have a number of contradictory manifestations from the viewpoint of the viability of the individual.These manifestations of a certain mutation can sometimes occur simultaneously; however, they also can occur in different phases of the life cycle of the individual.If a certain mutation has a favorable effect on the viability at an early stage in the life cycle and simultaneously a negative effect at a later stage in the cycle, it will become fixed in the population because, as was already explained in the previous section, the effectiveness of selection is greater in the early stages of the life cycle of an individual.It follows from this theory (Pedersen 1995)that the deterioration in viability during ageing is caused by the manifestations of accumulated mutations with antagonistic effects, to be more exact, by those that provide a selection advantage for a younger individual and simultaneously a disadvantage for an older individual (Fig. XII.7) {11593}.A mutation increasing the ability to regenerate tissue in a young individual which must almost necessarily simultaneously increase the risk of cancer in an older individual is a typical example.





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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
Draft translation from: Evoluční biologie, 2. vydání (Evolutionary biology, 2nd edition), J. Flegr, Academia Prague 2009. The translation was not done by biologist, therefore any suggestion concerning proper scientific terminology and language usage are highly welcomed. You can send your comments to flegratcesnet [dot] cz. Thank you.