It is known that a reformulation for variable population size of the classical Sewall Wright model for balance between two genotypes can lead, under some circumstances, to a situation of balanced polymorphism when there is no selection present. In this note it is shown that the presence of selection prohibits the possibility of balance and assures ultimate homozygosity with probability one. © 1977.
Heyde, C. C. (1977). The effect of selection on genetic balance when the population size is varying. Theoretical Population Biology, 11(2), 249–251. https://doi.org/10.1016/0040-5809(77)90027-2