Is there any mathematical model to predict the behaviour and long-term consequence of counter-acting selection at different time scale?
For example, let's consider the bi-allelic gene A, with alleles A1 and A2. During a long period of n1 generations A1 is slightly beneficial (differential of selection: s1). After this period, follows a short period of n2 generations when A2 is highly beneficial (differential of selection: s2).
What mathematical model describes the frequency fluctuations of alleles and which allele will get fixed at the long term given the initial frequency ( f0 ), assuming infinite population size and random mating.