Rare conditions are therefore disproportionately common in populations with strong founder events
With pure epistasis, the increase in additive genetic variance is not restricted to the founder event
but continues through succeeding generations until populations fixed at both loci become common.
The theoretical prediction of increased responsiveness to selection at the modifier loci has been elaborated and confirmed by subsequent theoretical work showing that founder events
can indeed convert epistatic variance into additive genetic variance, thereby increasing - not diminishing - the overall levels of additive genetic variance and hence selective responsiveness immediately after the founder event
(Goodnight 1988; Wagner et al.
The Lab population is genetically depauperate, most likely as a consequence of the founder event
, but this reduced variability contributes only trivially (about 1%) to the genetic differentiation between the populations.
see Provine 1989, Mayr 1992), opinions differ on whether founder events
ever lead to much loss of genetic variation (Lande 1980), or to major genetic reorganizations (Barton and Charlesworth 1984; Charlesworth and Rouhani 1988) and whether populations persist long enough at low density for strong inbreeding effects to occur (Parsons 1989).
The neutral effects of founder events
on the mean phenotype of a population have been well studied.
The expected heritability following a founder event
, making the assumptions listed above, is equal to the expected [V.
We conclude that although founder events
may occasionally lead to the evolution of assortative mating and hence to speciation, our results do not support the claim that the founder-flush-crash model identifies conditions very likely to result in speciation events.
However, the distance separating recolonized locations indicates that multiple founder events
likely occurred from streams east of the Wabash River.
Researchers can also use this information to develop an understanding of how the loss of genetic diversity often associated with founder events
may influence the evolution of invasive populations.
On the effect of founder events
on the epistatic genetic variance.
Bottlenecks or founder events
enhance genetic drift (Wright 1921, 1952; Wade and McCauley 1988; Whitlock and McCauley 1990; Whitlock 1992a,b).