As it happens, Genghis Khan is not the only historical proof of the Mathematical Impossibility of The Theory of Evolution by Natural Selection. Another very effective one is the Black Death, which left an observable mark on the genes of the descendants of those Europeans who survived it.
The CCR5-delta32 mutation is a 32-base-pair deletion in the CCR5 gene that, among other effects, confers significant resistance to HIV infection. This mutation is found almost exclusively in European populations, where it currently exists in approximately 10% of the population. Its geographic distribution and the nature of the selective pressure it confers have led scientific researchers to propose that it was positively selected during the Black Death pandemic of 1347-1351.
For our purposes, the precise historical cause of the mutation’s selection is less important than the observed rate of its historical propagation. What we know with certainty is that this mutation currently exists at approximately 10% frequency in European populations after roughly 27-34 generations, depending on the assumed generation length and the precise date of the selective event. Even using the most generous assumptions, using a starting frequency higher than a single individual, and permitting selection pressure from multiple historical events, the mutation remains far from fixation after nearly 700 years.
This means that a mutation providing resistance to a disease that killed between 30% and 60% of the European population, representing one of the strongest selective pressures in recorded human history, has only reached 10% frequency after roughly 30 generations. A linear extrapolation, which would be generous, as the rate of spread typically slows as a mutation approaches fixation due to diminishing selective advantage, shows that a Europe-wide fixation would require approximately 300 generations, or roughly 6,000-7,500 years.
This represents a fixation rate of approximately one mutation per 300 generations under extremely strong selective pressure within a geographically concentrated population. Compare this to the bacterial rate of one fixation per 1,600 generations. The human rate under optimal conditions is roughly five times faster than the bacterial rate, but only within a single continental population facing existential selective pressure. On a species-wide basis, accounting for the global distribution of humans and the dilution effect of populations not subject to the same selective pressure, the effective fixation rate would be considerably slower. Even if we grant the most favorable possible scenario to the Neo-Darwinians and assume:
- The highest estimate of dead Europeans at 50 million.
- The strongest selection pressure at 60 percent of the European population dead.
- The highest European percentage of the smallest global population, at 35.7 percent of the total human population of 350 million.
- The application of the same selective pressure on the non-European populations not exposed to the Black Death.
The shift from a European perspective to a global one that accounts for the entire human race increases the number of generations for fixation required to 840 generations and the time required to 16,800 years. Just dropping the estimated number of dead to the lower end of the range at 25 million and increasing the estimated global population to 400 million would push the generations required up to 1,440, and we still haven’t begun to account for the fact that the natural selection pressure would not be applicable to more than three-quarters of the total population.
The CCR5-delta32 example thus provides our first empirical data point: even under the strongest selective pressure ever observed in human history, mutations propagate through human populations at rates slower, not faster, than bacterial fixation in laboratory conditions.