This article is adapted from TJ 17(1), 2003. It shows that Humans and Chimps are not as identical in their chromosomes as previously though.
A recent report by the National Academy of Sciences suggests that the common value of >98% similarity of DNA between chimp and humans is incorrect. Roy Britten, author of the study, puts the figure at about 95% when insertions and deletions are included. However, there is more that meets the eyes then most people realise.
Archidiacono, N., Storlazzi, C.T., Spalluto, C., Ricco, A.S., Marzella, R., Rocchi, M. 1998. Evolution of chromosome Y in primates. Chromosoma 107:241-246.
The >98.5% similarity commonly used has been misleading because it depends on what is being compared. There are a number of significant differences that are difficult to quantify. The review by Gagneux and Varkidescribed resulted in a list of genetic differences between humans and the great apes. The differences include cytogenetic differences, differences in the type and number of repetitive genomic DNA and transposable elements, abundance and distribution of endogenous retroviruses, the presence and extent of allelic polymorphisms, specific gene inactivation events, gene sequence differences, gene duplications, single nucleotide polymorphisms, gene expression differences, and messenger RNA splicing variations.
Gagneux, P. and Varki, A. 2001. Genetic differences between humans and great apes. Mol Phylogenet Evol 18:2-13.
Specific examples of these differences include:
1) Humans have 23 pairs of chromosomes while chimpanzees have 24. Evolutionary scientists believe that one of the human chromosomes has been formed through the fusion of two small chromosomes in the chimp instead of an intrinsic difference resulting from a separate creation.
2) At the end of each chromosome is a string of repeating DNA sequences called a telomere. Chimpanzees and other apes have about 23 kilobases (a kilobase is 1,000 base pairs of DNA) of repeats. Humans are unique among primates with much shorter telomeres only 10 kilobases long.
Britten, R.J. 2002. Divergence between samples of chimpanzee and human DNA sequences is 5% counting indels. Proceedings National Academy Science 99:13633-13635
3) While 18 pairs of chromosomes are virtually identical, chromosomes 4, 9 and 12 show evidence of being remodeled. In other words, the genes and markers on these chromosomes are not in the same order in the human and chimpanzee. Instead of being remodeled as the evolutionists suggest, these could, logically, also be intrinsic differences because of a separate creation.
Gibbons, A. 1998. Which of our genes make us human? Science 281:1432-1434.
4) The Y chromosome in particular is of a different size and has many markers that do not line up between the human and chimpanzee
Archidiacono, N., Storlazzi, C.T., Spalluto, C., Ricco, A.S., Marzella, R., Rocchi, M. 1998. Evolution of chromosome Y in primates. Chromosoma 107:241-246.
5) Scientists have prepared a human-chimpanzee comparative clone map of chromosome 21 in particular. They observed large, non-random regions of difference between the two genomes. They found a number of regions that might correspond to insertions that are specific to the human lineage.
Fujiyama, A., Watanabe, H., Toyoda, A., Taylor, T.D., Itoh, T., Tsai, S.F., Park, H.S., Yaspo, M.L., Lehrach, H., Chen, Z., Fu, G., Saitou, N., Osoegawa, K., de Jong, P.J., Suto, Y., Hattori, M., and Sakaki, Y. 2002. Construction and analysis of a Human-Chimpanzee Comparative Clone Map. Science 295:131-134
6) The size of the chimpanzee genome is 10% greater than the size of the human genome.
Marks, J. 2000. 98% alike? (What our similarity to apes tells us about our understanding of genetics.) Chronicle of Higher Education May 12, 2000, B7.
These differences are usually not included in calculations of percent DNA similarity when counted by evolutionists.
In one of the most extensive studies comparing human and chimp DNA, the researchers compared >19.8 million bases. While this sounds like a lot, it still represents slightly less than 1% of the genome. They calculated a mean identity of 98.77% or 1.23% differences. However, this, like other studies only considered substitutions and did not take insertions or deletions into account as the new study by Britten did. A nucleotide substitution is a mutation where one base (A, G, C, or T) is replaced with another. An insertion or deletion (indel) is found where there are nucleotides missing when two sequences are compared.
Fujiyama, A., Watanabe, H., Toyoda, A., Taylor, T.D., Itoh, T., Tsai, S.F., Park, H.S., Yaspo, M.L., Lehrach, H., Chen, Z., Fu, G., Saitou, N., Osoegawa, K., de Jong, P.J., Suto, Y., Hattori, M., and Sakaki, Y. 2002. Construction and analysis of a Human-Chimpanzee Comparative Clone Map. Science 295:131-134.
The Britten study involved examining 779 kilobase pairs to highlight the differences between chimpanzees and humans. He found that 1.4% of the bases had been substituted, which was in agreement with previous studies (98.6% similarity). However, he found a much larger number of indels. Most of these were only 1 to 4 nucleotides in length, although there were a few that were > 1000 base pairs long. Surprisingly, the indels added an additional 3.4 % of base pairs that were different.
Britten, R.J. 2002. Divergence between samples of chimpanzee and human DNA sequences is 5% counting indels. Proceedings National Academy Science 99:13633-13635.
While previous studies have focused on base substitutions, the researchers have missed one of the greatest contribution to the genetic differences between chimps and humans. Missing nucleotides from one or the other appear to account for more than twice the number of substituted nucleotides. Although the number of substitutions is about ten times higher than the number of indels, the number of nucleotides involved in indels is greater. These indels were reported to be equally represented in the chimp and human sequences. Therefore, the insertions or deletions were not occurring only in the chimp or only in the human and could also be interpreted as intrinsic differences.
The similarity of chimpanzee and human DNA has now been reduced from >98.5% to ~95%. Moreover, using percentages hides an important fact. If 5% of the DNA is different, this amounts to 150,000,000 DNA base pairs that are different between them!
many studies have demonstrated a remarkable similarity in the nuclear DNA and mtDNA among modern humans. In fact, the DNA sequences for all people are so similar that scientists generally conclude that there is a recent single origin for modern humans, with general replacement of archaic populations.
Knight, A., Batzer, M.A., Stoneking, M., Tiwari, H.K., Scheer, W.D., Herrera, R.J., and Deninger, P.L. 1996. DNA sequences of Alu elements indicate a recent replacement of the human autosomal genetic complement. Proc. Natl Acad Sci USA 93:4360-4364.
To be fair, the estimates for a date of a most recent common ancestor (MRCA) by evolutionists has this recent single origin about 100,000-200,000 years ago, which is not recent by creationist standards. These estimates have been based on comparisons with chimpanzees and the assumption of a chimp/human common ancestor approximately 5 million years ago. In contrast, studies that have used pedigrees or generational mtDNA comparisons have yielded a much more recent MRCAeven 6,500 years!
Heyer, E., Zietkeiwicz, E., Rochowski, A., Yotova, V., Puymirat, J., and Labuda D. 2001. Phylogenetic and familial estimates of mitochondrial substitution rates: study of control region mutation in deep-rooting pedigrees. Am J Hum Genet 69:1113-1126.
Parsons T.J., Muniec, D.S., Sullivan, K., Woodyatt, N., Alliston-Greiner, R., Wilson, M.R., Berry, D.L., Holland, K.A., Weedn, V.W., Gill, P., and M.M. Holland. 1997. A high observed substitution rate in the human mitochondrial DNA control region. Nat. Genet. 15:363-368.
Sigurgardottir, S., Helgason, A., Gulcher, J.R., Stefansson, K., and Donnelly P. 2000. The mutation rate in the human mtDNA control region. Am J Hum Genet 66:1599-1609
Research on observable generational mutation events leads to a more recent common ancestor for humans than phylogenetic estimates that assume a relationship with chimpanzees. Mutational hotspots are believed to account for this difference. However, in both cases, they are relying on uniformitarian principlesthat rates measured in the present can be used to extrapolate the timing of events in the distant past.
Heyer, E., Zietkeiwicz, E., Rochowski, A., Yotova, V., Puymirat, J., and Labuda D. 2001. Phylogenetic and familial estimates of mitochondrial substitution rates: study of control region mutation in deep-rooting pedigrees. Am J Hum Genet 69:1113-1126.
The above examples demonstrate that the conclusions of scientific investigations can be different depending on how the study is done. Humans and chimps can have 95% or >98.5% similar DNA depending on which nucleotides are counted and which are excluded. Modern humans can have a single recent ancestor <10,000 or 100,000-200,000 years ago depending on whether a relationship with chimpanzees is assumed and which types of mutations are considered.
First of all i am not a theo-evo or a 6-24 hour day creationist. I have lots of reasons to have problems with both. To me these two groups do not take the Word of God seriously. the 6-24 hour day creationist are hard pressed to find their specific words (literal 24 hour days) in the Bible. That to me says they are only interested in furthering divisions in the body of Christ about a minor doctrine (Yes it is minor- it doesn't shake anything in the creeds of the church). The theo-evos try an apply man made scientist on the scripture and that obviously is wrong.
