Effective population size. 510 index page Introductory comments on random processes. The mathematics of probability yields some strange and often counter-intuitive expectations. The general difficulty most people have in understanding probability is powerfully demonstrated by huge profits earned by casinos and other gambling businesses. The following are some general points with some significance for understanding stochastic processes in evolution.
Random events are unaffected by what has gone before.
Here's an example which may be more intuitive. If you throw darts at a target, The most likely expectation for each dart is a bull's eye. Therefore, the most likely impact site must be the center, the average of all the scattered positions. Certainly no other particular position is more likely. For finite populations, the Hardy-Weinberg theorem gives the most likely expectation for gene frequencies after one round of random mating.