Human/chimp DNA similarity

Evidence for evolutionary relationship?

by Don Batten

The idea that human beings and chimps have close to 100% similarity in their DNA seems to be common knowledge. The figures quoted vary: 97%, 98%, or even 99%, depending on just who is telling the story.

What is the basis for these claims and do the data mean there really is not much difference between chimps and people? Are we just highly evolved apes?

The following concepts will assist with a proper understanding of this issue:

What if human and chimp DNA was even 96% homologous? What would that mean? Would it mean that humans could have ‘evolved’ from a common ancestor with chimps? Not at all! The amount of information in the 3 billion base pairs in the DNA in every human cell has been estimated to be equivalent to that in 1,000 books of encyclopaedia size.6 If humans were ‘only’ 4% different this still amounts to 120 million base pairs, equivalent to approximately 12 million words, or 40 large books of information. This is surely an impossible barrier for mutations (random changes) to cross.7

Ed. note: the point of this article was to refute one widely parroted ‘proof’ that humans evolved from apes, as should be clear from the title. It was simply beyond the scope of a single Creation magazine article to deal with all other ‘proofs’ of human evolution, although, amazingly, some atheistic sceptics have attacked this article for this alleged failing! But see Q&A: Anthropology (human ancestry, alleged ape-men) for addressing issues like alleged fossil ‘ape–men’.

References and notes

  1. However, Jeffrey Swartz, an evolutionary anthropologist at the University of Pittsburg, maintains that man is closer to orangutans in gross morphology. Acts and Facts, 16(5):5, 1987. Return to text.
  2. Sibley and Ahlquist, 1987, J. Molec. Evol. 26:99–121). The resulting hybrid duplex material is then separated from single–strand DNA remaining and heated in 2 to 3 degree increments from 55o to 95o C, and the amount of DNA separating at each temperature is measured and totalled, comparing it to human–human DNA re–formed as duplex. If 90% of the human DNA is recovered with heating from the human–chimp hybrid, compared to the human-human DNA, then there is said to be 90% normalised percentage hybridisation. Return to text.
  3. Sarich et al. 1989. Cladistics 5:3–32. Return to text.
  4. Ibid. Return to text.
  5. Molecular homology studies could be quite useful to creationists in determining what were the original created ‘kinds’ and what has happened since to generate new species within each kind. For example, the varieties / species of finch on the Galápagos Islands obviously derived from an original small number that made it to the islands. Recombination of the genes in the original migrants and natural selection could account for the varieties of finch on the islands today—just as all the breeds of dogs in the world today were artificially bred from an original wild dog/wolf kind not long ago. It is interesting that molecular homology studies have been most consistent when applied within what are probably biblical kinds and contradict the major predictions of evolution regarding the relationships between the major groups such as phyla and classes (see ref. 6 regarding the latter). Return to text.
  6. Denton, M., Evolution: Theory in Crisis. (Burnett Books, London), 1985. Return to text.
  7. Haldane’s Dilemma recognises the problem for evolutionists of getting genetic changes in higher organisms, especially those which have long generation times. Due to the cost of substitution (death of the unfit) of one gene for another in a population, it would take over 7x1011 years of human–like generations to substitute the 120 million base pairs. Or in 10 million years (twice the time since the chimp/human common ancestor is alleged to have lived), only 1667 substitutions could occur, or 0.001% of the difference. There has simply been insufficient time for ape–like creatures to turn into humans. And this understates the problem by assuming perfect efficiency of natural selection and ignoring deleterious processes like inbreeding and genetic drift, as well as problems posed by pleiotropy (one gene controlling more than one characteristic) and polygeny (more than one gene controlling one characteristic)—most real genes. See W.J. ReMine, The Biotic Message (St. Paul Science, St. Paul, Minnesota, 1993), pp. 215–217. Return to text.
However, Jeffrey Swartz, an evolutionary anthropologist at the University of Pittsburg, maintains that man is closer to orangutans in gross morphology. Acts and Facts, 16(5):5, 1987.
Sibley and Ahlquist, 1987, J. Molec. Evol. 26:99–121). The resulting hybrid duplex material is then separated from single–strand DNA remaining and heated in 2 to 3 degree increments from 55o to 95o C, and the amount of DNA separating at each temperature is measured and totalled, comparing it to human–human DNA re–formed as duplex. If 90% of the human DNA is recovered with heating from the human–chimp hybrid, compared to the human-human DNA, then there is said to be 90% normalised percentage hybridisation.
Sarich et al. 1989. Cladistics 5:3–32.
Ibid.
Molecular homology studies could be quite useful to creationists in determining what were the original created ‘kinds’ and what has happened since to generate new species within each kind. For example, the varieties / species of finch on the Galápagos Islands obviously derived from an original small number that made it to the islands. Recombination of the genes in the original migrants and natural selection could account for the varieties of finch on the islands today—just as all the breeds of dogs in the world today were artificially bred from an original wild dog/wolf kind not long ago. It is interesting that molecular homology studies have been most consistent when applied within what are probably biblical kinds and contradict the major predictions of evolution regarding the relationships between the major groups such as phyla and classes (see ref.
Denton, M., Evolution: Theory in Crisis. (Burnett Books, London), 1985.
Haldane’s Dilemma recognises the problem for evolutionists of getting genetic changes in higher organisms, especially those which have long generation times. Due to the cost of substitution (death of the unfit) of one gene for another in a population, it would take over 7x1011 years of human–like generations to substitute the 120 million base pairs. Or in 10 million years (twice the time since the chimp/human common ancestor is alleged to have lived), only 1667 substitutions could occur, or 0.001% of the difference. There has simply been insufficient time for ape–like creatures to turn into humans. And this understates the problem by assuming perfect efficiency of natural selection and ignoring deleterious processes like inbreeding and genetic drift, as well as problems posed by pleiotropy (one gene controlling more than one characteristic) and polygeny (more than one gene controlling one characteristic)—most real genes. See W.J. ReMine,

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