"OK, then, think about this," the Nurse barrelled on relentlessly, "we know that the forward and backward mutation rates for this particular allele pair are 10% and 20%. Will we always get the same equilibrium amounts of the two alleles?"

"Huh?"

"When you destroyed that last set of medical charts, you started with a population that was 400/100 for brown/blue alleles, and you got an equilibrium of 333/167. What if you started with 250/250? Or 100/400? Would the equilibrium still be 333/167?"

The Assistant looked alarmed and his writing hand quivered slightly.

"Never mind," said the nurse comfortingly. "I already worked these out -- just look at them...."