87  The human and chimpanzee genomes
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The difference between the genomes of humans and chimpanzees has been claimed in the past to be 1.5 to 2%. The molecular biologist Roy J. Britten has determined that, when the insertions and deletions are included in the calculation, the difference is nearly 5%. This means that at least 75 million “correct” mutations would have been necessary to make a modern human and a chimpanzee from a common ancestor. Even if one advantageous mutation per year (!) had occurred in these populations, a total of 75 million years would have been necessary (whereas the evolution of humanity is supposed to have taken only 2 million years). According to calculations by the genetic pioneer J.B.S. Haldane, a realistic estimation of the time that would have been required for this process is at least 2.5 billion years.

 
The scientific consensus today is that the difference between the genome of humans and chimpanzees amounts to 1.5 to 2%, purportedly supporting a relationship between apes and humans. However, the molecular biologist Roy J. Britten now determined that the difference is nearly 5% when the insertions and deletions are included in the calculation (1) (2). It is also possible that even a greater difference may be discovered, since only a small fraction of the genome has been compared to date. Of the total of 3 billion base pairs in the human genome, only about one million had been compared by the year 2008.


Differences between the human and chimpanzee genomes:


1) Humans have 23 chromosome pairs, chimpanzees 24.

2) There are special sequences at the end of each chromosome called telomeres. Apes have about 23 kilobase pairs, humans only 10.

3) Whereas 18 chromosome pairs are practically identical, the genes and markings are in a different order in chromosomes 4, 9 and 12.

4) The Y chromosome has a different size and many markings that do not match.

5) Chromosome 21 contains large regions that are completely different.

6) The chimpanzee genome is 11,5% larger than the human genome ...!


A book that can be recommended on this subject is “Genetic Entropy & the Mystery of the Genome”, published by the geneticist John C. Sanford in 2005. Sanford shows that the genome loses more and more information over time until the species goes extinct.


Haldane’s dilemma:

When a useful mutation occurs in a population, as many copies of it as possible must be distributed so that evolution can continue. In other words, the individuals that do not yet contain this mutation must be replaced. The rate at which this process can take place is, however, limited. One of the main limiting factors is the propagation rate of the given species. For a hominid species with a generation interval of 20 years and a low reproductive rate per individual, mutations spread very slowly through the population (3).

John B.S. Haldane (1892-1964) is one of the three founders of the modern science of population genetics. He assumed for a rough calculation a population of 100,000 ancestors in which one male and one female underwent a mutation at the same time (!) that was so beneficial that they outlived all the others (which is also highly unlikely). All the rest (the other 99,998) of the population died out and the surviving pair multiplied, eventually replenishing the entire population. This process would have to be repeated over the course of 10 million years in each generation (i.e. every 20 years) to introduce 500,000 (10,000,000 / 20) advantageous and perfectly adapted mutations into the population. These 500,000 mutations would then amount to only 0.02% of the necessary 5%. If more realistic rates of fitness / selection and population renewal are assumed, even 2.5 billion years will not be nearly enough.

Haldane’s dilemma was still a topic of discussion in scientific journals back in 1960, but the subject has been ignored since that time (4). This may be because mathematical modelling of such processes in population genetics is extremely complex. Research in the field today concentrates primarily on determining the number of advantageous mutations that can be determined to have actually occurred. Important elements that would enable us to continue with such calculations are still missing.

In 1992, the well-known evolutionary geneticist George C. Williams remarked, "…the time has come for renewed discussion and experimental attack on Haldane’s dilemma" (5). The appeal apparently produced no echo among his colleagues. Walter ReMine published a large study in 1993 in which he investigated the matter in detail (6). He continued work in this field, refined his arguments and addressed attempts by evolutionists who would like to obfuscate the matter. Unfortunately, no serious dispute of the matter has resulted to date. ReMine reminds us that Haldane’s dilemma has never been solved, but only hushed up, misrepresented and prematurely dismissed (7).


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References:

(1) Roy John Britten, Divergence between samples of chimpanzee and human DNA sequences is 5% counting indels, Proc. Nat. Acad. Sci., 99, USA, 2002, S. 13633–13635.
(2) David A. DeWitt, 98% Chimp/human DNA similarity? Not any more, Technical Journal 17/1, 2003, S. 8–10.
(3) John Burdon Sanderson Haldane, The cost of natural selection, Journal of Genetics 55, 1957, S. 511–524.
(4) Don Batten, Haldane’s Dilemma has not been solved, Technical Journal 19/1, 2005, S. 20–21.
(5) George Christopher Williams, Natural Selection: Domains, Levels and Challenges, Oxford University Press, NY, 1992, S. 143–144.
(6) Walter J. ReMine, The Biotic Message, St. Paul Science, St. Paul, MN, 1993.
(7) Walter J. ReMine, Cost theory and the cost of substitution - a clarification, Technical Journal 19/1, 2005, S. 113-125.
 
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