Some proponents of founder effect speciation models hypothesized that a period of dramatic population growth must follow the founder event, in part to prevent further loss of additive genetic variance (Carson 1968, 1982; Templeton 1980a,b; Carson and Templeton 1984).
Contrary to a commonly held view, although founder events and subsequent population bottlenecks certainly reduce genetic heterozygosity (Crow and Kimura 1970), they do not necessarily result in decreased additive genetic variance in the presence of dominance and/or epistasis.
Consider now a founder event
that would lead to fixation of an allele at this major locus, thereby instantly converting almost all epistatic interactions of other loci with this major locus into additive genetic variance.
If the founder event
caused the large differentiation observed between Lab and P1 or P2, this should be reflected in the corrected measure of genetic divergence.
We draw attention to the difference between the situation we studied and the situation usually modeled to explore the genetic consequences of founder events
Population bottlenecks or founder events
probably occur in almost all species at some times; however, there is a wide range of local population-size variation among species, and very little data about population sizes during bottlenecks (for references, see Whitlock 1992).
An extension of this line of reasoning holds that brief but intense periods of genetic drift, such as founder events
, might allow sufficient genetic change to cause reproductive isolation and speciation (Mayr 1954, 1963; Carson 1975; Templeton 1979, 1980; Carson and Templeton 1984).
Some models claim that speciation is often associated with founder events
Whether recolonization occurred through multiple founder events
or via small, surviving populations, the occurrence of H.
Epistasis and the effect of founder events
on the additive genetic variance.
or other reductions in effective population size "convert" nonadditive genetic variation to additive (i.
Although the specific genetic mechanisms were not fully articulated, similar processes were originally envisaged by Mayr (1954) and Carson (1968) in their models of speciation via founder events
or population bottlenecks.