Disruptive Selection


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Disruptive Selection

 

a type of natural selection in an animal or plant population resulting in the appearance of two or several new forms from a single inceptive one. For example, in the absence of food necessary for the growing young of perch, that is, the fingerlings of other fish, there may remain only “dwarfs” (individuals with severely retarded growth, who may feed for a long time on plankton crustaceans) and “giants” (individuals capable by the end of their first year of feeding on fingerling perch of their own generation). As a result of disruptive selection, in a number of years genetically conditioned races of giants and dwarfs are formed in a body of water.

References in periodicals archive ?
So, could disruptive selection have contributed to today's rainbow of birds?
First, the populations may be species that arose very recently and differentiated under strong disruptive selection. Second, the populations could be host races.
Disruptive selection in this species should favor a correlation between male morphology and male behavior, so that all guarding males have long horns, and all sneaking males are hornless.
To this end, the work reported in this study considers the genetical variation for host utilization of a herbivore population which had been subject to very limited, if any, disruptive selection with respect to plant-specific traits in the current generation, and considers the nature of this genetic variation after recombination.
saxatilis split because of disruptive selection in two conspecific morphs, one upper-shore and one lower-shore, that still maintain an important gene flux between them (Johannesson et al.
Compared to parametric regression, the cubic spline technique is better able to identify dips and modes that might indicate local stabilizing or disruptive selection in an otherwise directional selection surface.
Conversely, if the mean drifts sufficiently close to the saddle point, past the transition between stabilizing and disruptive selection, then increases in variance resulting from disruptive selection can change the mean fitness function enough to move the saddle point past the mean.
where [Alpha] = 2N[[Sigma].sup.2] is again a measure of the strength of selection and B = 1/c is a parameter reflecting the relative contributions of balancing and disruptive selection. For the TIM model, B = 1, and there is no balancing selection.
Shape.--To determine whether characters were under stabilizing or disruptive selection, rather than directional selection, we tested the regressions for second-order effects by entering the square of each standardized character into the regression models.
They applied disruptive selection to bristle number at two levels: moderate, in which the upper and lower 25% of individuals were selected for breeding, and high, in which the upper and lower 1% of individuals were selected.
The general patterns of stabilizing and disruptive selection are summarized in table 2.