How similar is human DNA to chimpanzee DNA? Richard Dawkins is a biologist from Oxford University. In 1986, he wrote: Chimpanzees and we share more than 99 percent of our genes.[1] As time has gone on, the percentage has lowered. Roy Britten is a molecular biologist from Princeton University. In 2002, after studying human and chimpanzee DNA, he wrote: The conclusion is the old saw that we share 98.5% of our DNA sequence with chimpanzee is probably in error. For this sample, a better estimate would be that 95% of the base pairs are exactly shared between chimpanzee and human DNA.[2] In 2003, one year later, a study published in Proceedings of the National Academy of Sciences (PNAS) showed that the similarity of human and chimpanzee DNA is only 86.7%.[3] Now, ten years later, what are the results? Jeffrey Tomkins is a geneticist from Clemson University. After comparing the DNA, he wrote: Genome-wide, only 70% of the chimpanzee DNA was similar to human under the most optimal sequence-slice conditions.[4] Does similar DNA imply ancestry? In any case, Jeffrey H. Schwartz, a physical anthropologist from Columbia University and John R. Grehan, a zoologist from Victoria University of Wellington, have written that similar DNA in different kinds of organisms does not imply a common ancestry for those organisms.[5] The University of Pittsburghs press release explains: Schwartz and Grehan contend in the Journal of Biogeography that ... molecular analyses that link humans to chimpanzees ... are often flawed: There is no theory holding that molecular similarity necessarily implies an evolutionary relationship; ... and molecular data that contradict the idea that genetic similarity denotes relation are often dismissed.[6] What are some examples of contradictory data? The journal Genome Research published a study showing that human and cat DNA is 90% similar.[7] If DNA similarity implies ancestry, then cats are more closely related to us than chimpanzees. Of course, nobody seriously believes we evolved from cats. The paper also claims that cat and dog DNA is only 82% similar. Why would humans be more closely related to cats than dogs are? The journal Science published a study showing that human and cow DNA is 80% similar.[8] Again, this would imply that cows are more closely related to us than chimpanzees are, which nobody believes. Also, youd expect horse DNA to be more similar to cow DNA than bat DNA, but according to a study published in PNAS, youd be wrong.[9] NewScientist reported the results of the study: YOU could call it a batty idea, but bats seem to be more closely related to horses than cows are. ... DNA analysis suggests that only cats and dogs are more closely related to horses than bats are (Proceedings of the National Academy of Sciences, DOI: 10.1073/pnas.0603797103). I think this will be a surprise for many scientists, says Norihiro Okada at the Tokyo Institute of Technology, Japan. No one expected this. [10] Laurence Pringle, in his childrens book called Billions of Years, Amazing Changes: The Story of Evolution, wrote: About eighty percent of platypus genes were the same as those found in humans, dogs, mice, and opossums. (The genes may be the same, but they are arranged in different ways in different species.)[11] Karen Hopkin is a biochemist from the Albert Einstein College of Medicine. She wrote that nearly 75% of human genes have some counterpart in nematodes—millimeter-long soil-dwelling worms.[12] Are worms more closely related to us than apes? Lisa Stubbs of Lawrence Livermore National Laboratory, Livermore, California, has written: Similarities between mouse and human genes range from about 70% to 90%, with an average of 85% similarity but a lot of variation from gene to gene (e.g., some mouse and human gene products are almost identical, while others are nearly unrecognizable as close relatives).[13] The journal Nature published a study showing that human and sponge DNA is 70% similar.[14] So, whos our closest living relative, the sponge or the chimpanzee? Other comparisons on the molecular level produce inconsistencies with the idea that similarity implies ancestry, suggesting that DNA comparisons are no different. Christian Schwabe was a biochemist and professor at Harvard Medical School until 1971. After making some of these molecular comparisons, he wrote: Against this background of high variability between relaxins from purportedly closely related species, the relaxins of pig and whale are all but identical. The molecules derived from rats, guinea-pigs, man and pigs are as distant from each other (approximately 55%) as all are from the elasmobranchs relaxin. ... Insulin, however, brings man and pig phylogenetically closer together than chimpanzee and man.[15] Schwabe also wrote: The relaxin and insulin families do not stand alone as exceptions to the orderly interpretation of molecular evolution in conventional monophyletic terms. It is instructive to look at additional examples of purportedly anomalous protein evolution and note that the explanations permissible under the molecular clock theories cover a range of ad hoc explanations apparently limited only by imagination.[16] Where are the additional examples of purportedly anomalous protein evolution? New Scientist magazine reported: Adrian Friday and Martin Bishop of Cambridge have analyzed the available protein sequence data for tetrapods ... To their surprise, in nearly all cases, man (the mammal) and chicken (the bird) were paired off as closest relatives, with the crocodile as next nearest relative ... [17] Some of our observations are surprising and indicate that similar DNA among different kinds of organisms has nothing to do with the level of genetic relatedness between these organisms. What about fruit flies? According to the National Human Genome Research Institute, about 60 percent of genes are conserved between fly and human. Or, to put it more simply, the two organisms appear to share a core set of genes.[18] Again, according to the National Human Genome Research Institute, [a]bout 60 percent of chicken genes correspond to a similar human gene.[19] These discoveries were not predicted by biologists who believe that DNA similarity implies ancestry. Sean Carroll is one of the worlds most eminent biologists. According to philosopher of science Michael Ruse, Of all the scientists in the world today, there is no one with whom Charles Darwin would rather spend an evening than Sean Carroll. Carroll wrote: No biologist had even the foggiest notion that such similarities could exist between genes of such different animals.[20] Why exactly is everyone so surprised? Well, it’s simply because creatures that supposedly diverged millions of years ago shouldn’t share the startling similarity in developmental genes that they do. For example, some scientists allege that humans once shared a common ancestor with fruit flies. However, since we diverged so long ago, any similar genes we shared should’ve been scrambled beyond recognition by almost countless generations of mutations. This is why Ernst Mayr, a man once described as the world’s greatest living evolutionary biologist stated, the search for homologous [i.e., similar] genes is quite futile except in very close relatives.[21] But this is wrong. Not only do we share similar developmental genes with fruit flies, but also with almost every other creature on the planet! Its not only animals though. John Stephen Jones is a geneticist from the University of Edinburgh. In an interview, he said: We also share about 50% of our DNA with bananas and that doesnt make us half bananas, either from the waist up or the waist down.[22] Jonathan M. Marks is a biological anthropologist from the University of Arizona. According to him, the DNA of the daffodil flower is about 35% identical to human DNA.[23] Jerry Bergman and Jeffrey Tomkins write: ... but it does not follow that we are physically 35% daffodil.[24] What is the simplest inference that can be drawn from the similarities in DNA that we observe in different kinds of organisms? That they represent something other than the degree of genetic relatedness and the degree of similarity in physical shape among these organisms. References: [1] Dawkins, R., The Blind Watchmaker: Why the Evidence of Evolution Reveals a Universe Without Design (W.W. Norton, New York, 1986) p. 263. [2] Roy J. Britten, Divergence between samples of chimpanzee and human DNA sequences is 5%, counting indels, Proc. Nat. Acad. Sci. 99(21):13633–13635, (2002); [3] Tatsuya, A., et al., Comparative Sequencing of Human and Chimpanzee MHC Class I Regions Unveils Insertions/Deletions As the Major Path to Genomic Divergence, Proc. Nat. Acad. Sci. 100(13):7708–7713 (2003); [4] Jeffrey P. Tomkins, Comprehensive Analysis of Chimpanzee and Human Chromosomes Reveals Average DNA Similarity of 70% Answers Research Journal 6:63–69 (February 20, 2013); [5] John R. Grehan and Jeffrey H. Schwartz, Evolution of the second orangutan: phylogeny and biogeography of hominid origins, Journal of Biogeography 36(10):1823–1844 (2009); [6] B. Rose Huber, Humans Related to Orangutans, Not Chimps, Says New Pitt, Buffalo Museum of Science Study of Human Origin, University of Pittsburgh (June 17, 2009); [7] Joan U. Pontius, et al., Initial sequence and comparative analysis of the cat genome, Genome Research 17(11):1675–1689 (November 2007); [8] The Bovine Genome Sequencing and Analysis Consortium, Christine G. Elsik, Ross L. Tellam, Kim C. Worley, The Genome Sequence of Taurine Cattle: A Window to Ruminant Biology and Evolution, Science 324(5926):522–528 (April 2009); [9] Hidenori Nishihara, Masami Hasegawa, Norihiro Okada, Pegasoferae, an unexpected mammalian clade revealed by tracking ancient retroposon insertions, Proc. Nat. Acad. Sci. 103(26):9929–9934 (May 9, 2006); [10] Bats and horses get strangely chummy, NewScientist (June 25, 2006); [11] Laurence Pringle, Billions of Years, Amazing Changes: The Story of Evolution (Boyds Mills Press, Inc., Pennsylvania, USA, 2011), pp. 49–50; [12] Karen Hopkin, The Greatest Apes, New Scientist 62(2186):27 (May 15, 1999); [13] Functional and Comparative Genomics Fact Sheet, Human Genome Project Information; [14] Mansi Srivastava, et al., The Amphimedon queenslandica genome and the evolution of animal complexity, Nature 466(7307):720–726 (August 5, 2010); [15] Christian Schwabe, Theoretical Limitations of Molecular Phylogenetics and the Evolution of Relaxins, Comparative Biochemical Physiology 107B:171–172; [16] Christian Schwabe and Gregory W. Warr, A polyphyletic view of evolution: the genetic potential hypothesis, Perspectives in Biology and Medicine 27(3):473 (Spring 1984); [17] Mike Benton, Is a Dog More Like a Lizard or a Chicken? New Scientist 103:19 (August 16, 1984). [18] National Human Genome Research Institute, Backround on Comparative Genomic Analysis, National Institutes of Health (December 2002); [19] National Human Genome Research Institute, Researchers Compare Chicken, Human Genomes, National Institutes of Health (Dec. 8, 2004); [20] Carroll, S.B., Endless Forms Most Beautiful: The New Science of Evo Devo (W.W. Norton & Company, New York, 2005), p. 64. [21] Ref. 20, pp. 71–74. [22] John Stephen Jones, interviewed at the Australian Museum on The Science Show, broadcast on ABC radio, (January 12, 2002); [23] Marks, J., What it Means to Be 98% Chimpanzee: Apes, People and Their Genes (Berkeley and Los Angeles, CA, University of California Press, 2002), p. 29. [24] Jerry Bergman and Jeffrey Tomkins, Is the human genome nearly identical to chimpanzee?—a reassessment of the literature, Journal of Creation 26(1):58 (April 2012);
Posted on: Fri, 06 Jun 2014 15:02:46 +0000