The present paper continues the work of two previous papers on the
variational behavior, over a large number of generations, of a Wright-Fisher
process modelling an even larger reproducing population. It was shown that a
Wright-Fisher process subject to random drift and one-way mutation which
undergoes a large deviation follows with near certainty a path which can be a
trigonometric, exponential, hyperbolic or parabolic function. Here it is shown
that a process subject to random drift and gamete selection follows in similar
circumstances a path which is, apart from critical cases, a Jacobian elliptic
function.