SOME RELATIONS BETWEEN DIFFERENT CHARACTERISTICS OF SELECTION

Consider the action of selection with fitness w(x) on a quantitative t rait x. What selection, among those that produce the same value of sel ection differential, leads to minimal values of(a) genetic load, (b) v ariance of the relative fitness, and (c) variance of the trait after s election? We have shown that for (a) and (c) the answer is strict trun cation, whereas for (b) the answer is linear selection. The results fo r (a) and (b) are true for any selection, while the result for (c) is true only for directional selection. Implications of these findings ar e discussed.