  For multivariant Wright-Fisher models in population genetics, we introduce
equilibrium states, expressed by fluctuations of probability ratio, in contrast
to the traditionally used fluctuations, expressed by the difference between the
current value of the random process and its equilibrium value. Then the drift
component of the dynamic process of gene frequencies, primarily expressed as a
ratio of two quadratic forms, is transformed into a cubic parabola with a
certain normalization factor.
