Posted on 10/11/2006 12:36:08 AM PDT by Tarnsman
True enough. Birds are well-known for the males' role in raising young. But I think for primates fatherhood is pretty much limited to humans in the true sense of the word.
Greater than 98% Chimp/human DNA similarity? Not any more.
A common evolutionary argument gets reevaluated—by evolutionists themselves.
by David DeWitt
A new report in the Proceedings of the National Academy of Sciences suggests that the common value of >98% similarity of DNA between chimp and humans is incorrect.2 Roy Britten, author of the study, puts the figure at about 95% when insertions and deletions are included. Importantly, there is much more to these studies than people realize.
The >98.5% similarity has been misleading because it depends on what is being compared. There are a number of significant differences that are difficult to quantify. A review by Gagneux and Varki4 described 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.’4
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.7
3. While 18 pairs of chromosomes are ‘virtually identical’, chromosomes 4, 9 and 12 show evidence of being ‘remodeled.’5 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.
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.1
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.’3
These types of differences are not generally included in calculations of percent DNA similarity.
In one of the most extensive studies comparing human and chimp DNA,3 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.
Figure 1.
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Comparison between a base substitution and an insertion/deletion. Two DNA sequences can be compared. If there is a difference in the nucleotides (an A instead of a G) this is a substitution. In contrast, if there is a nucleotide base which is missing it is considered an insertion/deletion. It is assumed that a nucleotide has been inserted into one of the sequences or one has been deleted from the other. It is often too difficult to determine whether the difference is a result of an insertion or a deletion and thus it is called an ‘indel’. Indels can be of virtually any length.
The Britten2 study looked at 779 kilobase pairs to carefully examine 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.
While previous studies have focused on base substitutions, they have missed perhaps 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.
Will evolution be called into question now that the similarity of chimpanzee and human DNA has been reduced from >98.5% to ~95%? Probably not. Regardless of whether the similarity was reduced even below 90%, evolutionists would still believe that humans and apes shared a common ancestor. 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!
A number of 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.’8 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 comparisons6, 10, 11 have yielded a much more recent MRCA—even 6,500 years!10
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.6 However, in both cases, they are relying on uniformitarian principles—that rates measured in the present can be used to extrapolate the timing of events in the distant past.
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.
References
1. 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.
2. 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. 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.
4. Gagneux, P. and Varki, A. 2001. ‘Genetic differences between humans and great apes.’ Mol Phylogenet Evol 18:2-13.
5. Gibbons, A. 1998. ‘Which of our genes make us human?’ Science 281:1432-1434.
6. 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.
7. Kakuo, S., Asaoka, K. and Ide, T. 1999. ‘Human is a unique species among primates in terms of telomere length.’ Biochem Biophys Res Commun 263:308-314.
8. 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.
9. 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.
10. 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.
Available online at:
http://www.answersingenesis.org/tj/v17/i1/DNA.asp
COPYRIGHT © 2006 Answers in Genesis
Marmoset Monkeys from http://www.financialexpress.com/fe_full_story.php?content_id=137937
“Marmosets are unusual among mammals as the fathers care extensively for offspring”. Gould and her researchers previously found brain changes in other adult mammals, such as rats that grew new neurons when they became dominant in a small community, Princeton Weekly Bulletin reported last year.
Bill Clinton found wandering in the zoo, muttering something about mean little monkeys two days later.
Chimp genome sequence very different from man
by David A. DeWitt, Ph.D., director, Center for Creation Studies, Liberty University, Lynchburg, VA, USA
September 5, 2005
For many years, evolutionary scientists—and science museums and zoos—have hailed the chimpanzee as “our closest living relative” and have pointed to the similarity in DNA sequences between the two as evidence. In most previous studies, they have announced 98-99% identical DNA.1 However, these were for gene coding regions (such as the sequence of the cytochrome c protein), which constituted only a very tiny fraction of the roughly 3 billion DNA base pairs that comprise our genetic blueprint. Although the full human genome sequence has been available since 2001, the whole chimpanzee genome has not. Thus, all of the previous work has been based on only a portion of the total DNA.
Last week, in a special issue of Nature devoted to chimpanzees, researchers report the initial sequence of the chimpanzee genome.2 No doubt, this is a stunning achievement for science: deciphering the entire genetic make up of the chimpanzee in just a few years. Researchers called it “the most dramatic confirmation yet” of Darwin’s theory that man shared a common ancestor with the apes. One headline read: “Charles Darwin was right and chimp gene map proves it.”3
So what is this great and overwhelming “proof” of chimp-human common ancestry? Researchers claim that there is little genetic difference between us (only 4%). This is a very strange kind of proof because it is actually double the percentage difference that has been claimed for years!4 The reality is, no matter what the percentage difference, whether 2%, 4%, or 10%, they still would have claimed that Darwin was right.
Further, the use of percentages obscures the magnitude of the differences. For example, 1.23% of the differences are single base pair substitutions. This doesn’t sound like much until you realize that it represents ~35 million mutations! But that is only the beginning, because there are ~40–45 million bases present in humans and missing from chimps, as well as about the same number present in chimps that is absent from man. These extra DNA nucleotides are called “insertions” or “deletions” because they are thought to have been added in or lost from the sequence. (Substitutions and insertions are compared in Figure 1.) This puts the total number of DNA differences at about 125 million. However, since the insertions can be more than one nucleotide long, there are about 40 million separate mutation events that would separate the two species.
Figure 1.
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Substitution
Insertion/deletion
Comparison between a base substitution and an insertion/deletion. Two DNA sequences can be compared. If there is a difference in the nucleotides (an A instead of a G) this is a substitution. In contrast, if there is a nucleotide base which is missing it is considered an insertion/deletion. It is assumed that a nucleotide has been inserted into one of the sequences or one has been deleted from the other. It is often too difficult to determine whether the difference is a result of an insertion or a deletion and thus it is called an “indel.” Indels can be of virtually any length.
To put this number into perspective, a typical page of text might have 4,000 letters and spaces. It would take 10,000 such full pages of text to equal 40 million letters! So the differences between humans and chimpanzees include ~35 million DNA bases that are different, ~45 million in the human that are absent from the chimp and ~45 million in the chimp that are absent from the human.
Creationists believe that God made Adam directly from the dust of the earth just as the Bible says. Therefore, man and the apes have never had an ancestor in common. However, assuming they did for the sake of analyzing the argument, then 40 million separate mutation events would have had to take place and become fixed in the population in only ~300,000 generations—a problem referred to as “Haldane’s dilemma.” This problem is exacerbated because the authors acknowledge that most evolutionary change is due to neutral or random genetic drift. That refers to change in which natural selection is not operating. Without a selective advantage, it is difficult to explain how this huge number of mutations could become fixed in the population. Instead, many of these may actually be intrinsic sequence differences from the beginning of creation.
Some scientists are surprised at the anatomical, physical and behavioral differences between man and chimpanzee when they see so much apparent genetic similarity. With a philosophy that excludes a Creator God, they are forced to accept similarity as evidence of common ancestry. However, similarity can also be the result of a common Designer.
It is the differences that make the difference. The most important difference is that man is created in the image of God.
Dr. DeWitt is the director of the Center for Creation Studies and an associate professor of biology at Liberty University in Lynchburg, Virginia, USA. His Ph.D. is in neurosciences from Case Western Reserve University and the focus of his research is the cell biology of Alzheimer’s disease. Dr. DeWitt was a featured speaker at July’s “Creation Mega Conference” where one of his presentations was titled “Image of God or Planet of Apes.” This talk, which will soon be available on DVD, deals with molecular and anatomical distinctions between man and the apes.
Recommended resources
References
1. DeWitt, D.A., >98.5% Chimp human DNA similarity? Not anymore.
2. The Chimpanzee Sequencing and Analysis Consortium 2005. “Initial sequence of the chimpanzee genome and comparison with the human genome,” Nature 437:69–87.
3. www.news-medical.net/?id=12840, August 31 2005.
4. Studies of chimp-human similarity have typically ignored insertions and deletions although this accounts for most of the differences. A study by Roy Britten included these insertions and deletions and obtained a figure that is close to the 4% reported here. Britten, R.J., “Divergence between samples of chimpanzee and human DNA sequences is 5% counting indels,” Proceedings National Academy Science 99:13633–13635, 2002.
Available online at:
http://www.answersingenesis.org/docs2005/0905chimp.asp
COPYRIGHT © 2006 Answers in Genesis
Staircases without landings.
"Among chimps, males hang out in groups, form alliances, forage together, and do a lot of bickering over status."
Sounds like the female of our species :)
"the bachelor herd", a disturbing phenomena amongst Muslims, the Chinese and Indians.
Oh man I am glad my wife didn't see that your post. I would have gotten an earful.
This guy is a scientist?
Thanks for the ping!
"the bachelor herd"
Explains a lot when you think about it. Wonder if anyone has applied that notion to the barbarian invasions of ancient times.
Is that Why most democrats are women?...
We could have gotten the same information content if you had just printed that.
Scientific disinformation and sabotage is this organization's specialty - and they're not even very good at it.
Now I understand - it's "long maturation".
Not that I've noticed, though the two do seem to keep waging advertising mailings against one another. That said, it is some months since my subscription expired.
The larger East African chimp, where males predominate, produced the line that led to humanity.
That's pure Barbara Striesand. Chimps did not start the line that led to humanity. Rather, chimps and humans are branches coming off a common line.
Any reasonably well-educated middle school student could have told you that.
You are just wrong. There are good, hard working PhD scientists on their staff. You dismiss their conclusions just because they don't buy into a materialistic worldview. Someday, set aside your prejudice, and read their work. You might be surprised.
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