  The Y-chromosome degeneration is still an intriguing mechanism and comprises
the very origin of sex. We present a coupled version of the well known logistic
map and the logistic equation describing the evolution of XY chromosomes.
Although chaos was found in X, Y chromosomes do not evolve chaotically. A
mathematical constraint is shown as the responsible for this behaviour. In
addition, analytical solutions are presented for the differential equations
herein.
