The maintenance of polygenic variation through a balance between mutation and stabilising selection

article The maintenance of polygenic variation through a balance between mutation and stabilising selection published yes Nicholas H Barton author 4880FE40-F248-11E8-B48F-1D18A9856A870000-0002-8548-5240 The maintenance of polygenic variation through a balance between mutation and stabilizing selection can be approximated in two ways. In the ‘Gaussian’ approximation, a normal distribution of allelic effects is assumed at each locus. In the ‘House of Cards’ approximation, the effect of new mutations is assumed to be large compared with the spread of the existing distribution. These approximations were developed to describe models where alleles may have a continuous range of effects. However, previous analyses of models with only two alleles have predicted an equilibrium variance equal to that given by the ‘House of Cards’ approximation. These analyses of biallelic models have assumed that, at equilibrium, the population mean is at the optimum. Here, it is shown that many stable equilibria may coexist, each giving a slight deviation from the optimum. Though the variance is given by the ‘House of Cards’ approximation when the mean is at the optimum, it increases towards a value of the same order as that given by the ‘Gaussian’ approximation when the mean deviates from the optimum. Thus, the equilibrium variance cannot be predicted by any simple model, but depends on the previous history of the population. Cambridge University Press1986 eng Genetical Research 0016-6723 1469-5073 374404610.1017/S0016672300023156 473209 - 216 yes N.H. Barton, Genetical Research 47 (1986) 209–216. Barton NH. The maintenance of polygenic variation through a balance between mutation and stabilising selection. Genetical Research. 1986;47(3):209-216. doi:<a href="https://doi.org/10.1017/S0016672300023156">10.1017/S0016672300023156</a> N. H. Barton, “The maintenance of polygenic variation through a balance between mutation and stabilising selection,” Genetical Research, vol. 47, no. 3. Cambridge University Press, pp. 209–216, 1986. Barton, Nicholas H. “The Maintenance of Polygenic Variation through a Balance between Mutation and Stabilising Selection.” Genetical Research. Cambridge University Press, 1986. <a href="https://doi.org/10.1017/S0016672300023156">https://doi.org/10.1017/S0016672300023156</a>. Barton NH. 1986. The maintenance of polygenic variation through a balance between mutation and stabilising selection. Genetical Research. 47(3), 209–216. Barton, N. H. (1986). The maintenance of polygenic variation through a balance between mutation and stabilising selection. Genetical Research. Cambridge University Press. <a href="https://doi.org/10.1017/S0016672300023156">https://doi.org/10.1017/S0016672300023156</a> Barton, Nicholas H. “The Maintenance of Polygenic Variation through a Balance between Mutation and Stabilising Selection.” Genetical Research, vol. 47, no. 3, Cambridge University Press, 1986, pp. 209–16, doi:<a href="https://doi.org/10.1017/S0016672300023156">10.1017/S0016672300023156</a>. 43242018-12-11T12:08:15Z2022-01-31T14:31:48Z