Sympatric speciation from disruptive selection
assumes that a large
Lyon describes disruptive selection
as one of three ways evolution shifts a trait.
In spite of the high variance in relative fitness, no significant linear ([beta]') and nonlinear ([gamma]') gradients of selection were detected, indicating an absence of directional and stabilizing/ disruptive selection
on spine length (Table 5).
on habitat preference and the evolution of assortative mating: a simulation study.
On the maintenance of genetic variation by disruptive selection
among hosts in a phytophagous mite.
To test our hypotheses on disruptive selection
and the mode of inheritance of survival ability, we measured the survival of pure host races and hybrids in an experimental garden.
For all species but Gadwall, variation was the same for scores of unsuccessful and successful nest sites (Table 3), which excludes disruptive selection
for these species.
2b also shows that the populations resulting from disruptive selection
on constitutive levels of myrosinase did not also differ significantly in constitutive levels of glucosinolates.
Stabilizing and disruptive selection
gradient estimates were nonsignificant (all P [greater than] 0.
acuminatus probably experience disruptive selection
on male horns (Emlen 1994b; Emlen, unpubl.
Uniform stabilizing selection on an additive character generates disruptive selection
at the genetic level because various combinations of alleles can yield the same optimal phenotype, but the marginal fitness of any allele depends on the genetic background in which it is found (Wright 1935).
Negative covariance for a character across environments may arise from (1) antagonistic pleiotropy or (2) linkage disequilibrium, caused by either genetic drift or disruptive selection
on epistatic loci (Futuyma and Philippi, 1987; Via 1991).