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Mutational robustness (also called mutation tolerance) describes the extent to which an organism's phenotype remains constant in spite of mutation. [9] Robustness can be empirically measured for several genomes [10] [11] and individual genes [12] by inducing mutations and measuring what proportion of mutants retain the same phenotype, function or fitness.
The classical example is the Drosophila w m4 (speak white-mottled-4) translocation. In this mutation , an inversion on the X chromosome placed the white gene next to pericentric heterochromatin, or a sequence of repeats that becomes heterochromatic. [ 3 ]
Recurrent evolution also referred to as repeated [1] [2] or replicated [3] evolution is the repeated evolution of a particular trait, character, or mutation. [4] Most evolution is the result of drift, often interpreted as the random chance of some alleles being passed down to the next generation and others not.
In comparison, an evolutionarily stable state describes a population that returns as a whole to its previous composition even after being disturbed. [1] In short: the ESS refers to the strategy itself, uninterrupted and supported through natural selection, while the evolutionarily stable state refers more broadly to a population-wide balance of ...
Cases of mutation bias are cited by mutationism advocates of the extended evolutionary synthesis who have argued that mutation bias is an entirely novel evolutionary principle. This viewpoint has been criticized by Erik Svensson. [ 74 ]
Height − Another example of a trait, that might be acted on by stabilizing selection, is plant height. A plant that is too short may not be able to compete with other plants for sunlight. However, extremely tall plants may be more susceptible to wind damage. Combined, these two selection pressures select to maintain plants of medium height.
Nevertheless, the concept is still widely used in evolutionary genetics, e.g. to explain the persistence of deleterious alleles as in the case of spinal muscular atrophy, [5] [4] or, in theoretical models, mutation-selection balance can appear in a variety of ways and has even been applied to beneficial mutations (i.e. balance between selective ...
Coalescent theory is a model of how alleles sampled from a population may have originated from a common ancestor.In the simplest case, coalescent theory assumes no recombination, no natural selection, and no gene flow or population structure, meaning that each variant is equally likely to have been passed from one generation to the next.