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In evolutionary biology, disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups.
The first is directional selection, which is a shift in the average value of a trait over time—for example, organisms slowly getting taller. [80] Secondly, disruptive selection is selection for extreme trait values and often results in two different values becoming most common, with selection against the average value. This would be when ...
disruptive selection. Also diversifying selection. A mode of natural selection in which the extreme values of a trait or phenotype within a breeding population are favored over intermediate values, causing allele frequencies to shift over time away from the intermediate. This causes the variance in the trait to increase and results in the ...
Genetic divergence will always accompany reproductive isolation, either due to novel adaptations via selection and/or due to genetic drift, and is the principal mechanism underlying speciation. On a molecular genetics level, genetic divergence is due to changes in a small number of genes in a species, resulting in speciation . [ 2 ]
Gene selection acts directly at the level of the gene. In kin selection and intragenomic conflict, gene-level selection provides a more apt explanation of the underlying process. Group selection, if it occurs, acts on groups of organisms, on the assumption that groups replicate and mutate in an analogous way to genes and individuals. There is ...
Under conditions of genetic drift alone, every finite set of genes or alleles has a "coalescent point" at which all descendants converge to a single ancestor (i.e. they 'coalesce'). This fact can be used to derive the rate of gene fixation of a neutral allele (that is, one not under any form of selection) for a population of varying size ...
Microevolution is the change in allele frequencies that occurs over time within a population. [1] This change is due to four different processes: mutation, selection (natural and artificial), gene flow and genetic drift. This change happens over a relatively short (in evolutionary terms) amount of time compared to the changes termed macroevolution.
Disruptive selection acts because there is negative selection for intermediate phenotypes, where as diversifying selection operates by way of positive selection for extreme phenotypes, such that assuming a continuous linear phenotype-space disruptive selection results in a bimodal distribution of phenotypes, whereas diversifying selection ...