Just to put it on the record, I thought it would be useful to examine the challenge posed by the post-CHLCA genetic distance between Chimpanzee and Human based on the substitution rates estimated by two great evolutionary biologists, JBS Haldane and Motoo Kimura, as published by the latter in his extremely influential 1968 paper, Evolutionary Rate at the Molecular Level.
In the evolutionary history of mammals, nucleotide substitution has been so fast that, on average, one nucleotide pair has been substituted in the population roughly every 2 yr. This figure is in sharp contrast to Haldane’s well known estimate that, in horotelic evolution (standard rate evolution), a new allele may be substituted in a population roughly every 300 generations.
I’ve summarized their estimates, and the consequences of those estimates, in the same manner that I originally summarized my own estimates in my 2019 post entitled Maximal Mutations. Note that I have, in the interest of accuracy and on the recommendation of DeepSeek, changed the years per generation from 20 to 25, as I am informed that “25 years is a widely accepted average in genetics and anthropology.” Also note that Kimura utilizes the term “substitution” instead of “fixation”, but he means the same thing, which is the establishment of the nucleotide pair, also known as “base pair”, throughout the entire population. And finally, note that due to Haldane’s reference to alleles, not base pairs, the maximum number of fixed mutations for his model needs to be multiplied by 1.4, since that is the realistic weighted average of base pairs per allele.
And remember, literally none of these numbers or estimates are of my invention. All I have done is to apply the relevant math to their estimates, which apparently no one in the entire scientific community has ever bothered to do.
HALDANE
Years: 9,000,000
Years per generation: 25
Generations per fixed mutation: 300
Years per fixed mutation: 7,500
Maximum fixed mutations: 1,200
Genomic Difference in base pairs: 30,000,000
Genomic Shortfall in base pairs: 29,998,800
Percent Accounted For: 0.004 percent
KIMURA
Years: 9,000,000
Years per generation: 25
Generations per fixed mutation: 0.08
Years per fixed mutation: 2
Maximum fixed mutations: 4,500,000
Genomic Difference in base pairs: 30,000,000
Genomic Shortfall in base pairs: 25,500,000
Percent Accounted For: 15 percent
The problem should be glaringly apparent. Even if we apply Kimura’s insanely fast estimate of an average 2-year population-wide fixation rate for every new mutation entering the gene pool, a rate that is obviously impossible to attain for either humans or chimpanzees, his neutral selection theory can neither explain nor account for 85 percent of the observed genomic differences between modern chimpanzees and modern humans.
It’s even worse for traditional natural selection theory, as the 300 generations per fixation rate provided in Haldane’s 1957 paper, The Cost of Natural Selection, means that Neo-Darwinian natural selection can only account for four-thousandths of one percent of the observed genomic differences.
There is no theory of evolution that is capable of even coming close to accounting for the situation we observe today.
On a related subject, my favorite illustrator had a request. Not, of course, for her benefit, but for the good of others, because she is a very kind individual with a good heart.
Is there an article or something that can explain what a “rate of fixation” is for dumb people? Not me of course, just some dumb people I know. Like a really dumbed down version of what Vox is getting at. I mean, I kind of get it… in my heart… but I don’t understand it enough to paraphrase it.
Rate of fixation = the time it takes for every single member of the same generation across the entire population to be born with the same nucleotide pair after that specific nucleotide pair first appeared as a mutation in a single individual.
Let us imagine that a baby being born with six fingers on his left hand was the result of a unique mutation of a single nucleotide pair. The rate of fixation would be how many years after the birth of that child passed before a generation appeared in which every single child in the entire human race was born with six fingers on their left hand.
There are 30 million or so nucleotide pairs that separate the human genome from the chimpanzee genome, each of which first appeared at some point and propagated through the whole of one of the two populations in the last 9 million years that have passed since the Last Chimp-Human Common Ancestor, according to standard evolutionary theory. This did not happen because it could not have happened.
As I have demonstrated above, whether you apply Haldane’s natural selection or Kimura’s neutral selection, nowhere nearly enough time has passed to account for the current differences between the two genomes because the rate of fixation is far too slow to do so.
UPDATE: It’s not possible to simply divide the 30 million difference between human and chimp and calculate on the basis of 15 million mutations over 9 million years. We have no idea whether the division should be 50/50 or 90/10, and we can’t know where it should be until the LCHCA genome is sequenced.