Search results
Results from the WOW.Com Content Network
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.
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 ]
These two alleles can turn out to be incompatible, which are the Dobzhansky–Muller incompatibilities. [5] The model states that genetic incompatibility is most likely evolved by alternative fixation of two or more loci instead of just one, so that when hybridisation occurs, it is the first time for some of the alleles to co-occur in the same ...
An alternative model exists to address the antagonism of recombination, as it can reduce the association between the alleles that involve fitness and the assortive mating alleles that do not. [15] Genetic models often differ in terms of the number of traits associated with loci; [29] with some relying on one locus per trait [26] [30] [31] and ...
Balancing selection refers to a number of selective processes by which multiple alleles (different versions of a gene) are actively maintained in the gene pool of a population at frequencies larger than expected from genetic drift alone. Balancing selection is rare compared to purifying selection. [1] It can occur by various mechanisms, in ...
If dioecious organisms are heterogametic and the gene locus is located on the X chromosome, it can be shown that if the allele frequencies are initially unequal in the two sexes [e.g., XX females and XY males, as in humans], f′(a) in the heterogametic sex 'chases' f(a) in the homogametic sex of the previous generation, until an equilibrium is ...
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 ...