To emphasize the statistically random nature of our inheritance and the huge gene pool involved, consider this: how many ancestors did you have at the time of the american revolution? for convenience, let’s call this a 225-year period. let’s also allot 25 years to each generation - the time between one’s birth and the birth of his/her first child. (this is only a mathematical projection backward in time; there is no assumption that anyone today knows the identity of these individuals.)

twenty-five years might be an unrealistic estimate of generation time. let’s re-figure, using twenty years as the generation time, and, more nearly accurately, 240 years as the time span since the revolution. now how many ancestors do you predict?

either way, these are large numbers of people. here’s another surprise. as the numbers continue to double with each generation back in time, the predicted number of ancestors will eventually exceed the estimated population of the world at that time. how can this be explained?