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Smaterthanhick for your reading pleasure,it's time for you to catch up.
REAL GENOMIC DIFFERENCES
One of the downfalls of previous molecular genetic studies has been the limit at which chimpanzees and humans could be compared accurately. Scientists often would use only 30 or 40 known proteins or nucleic acid sequences, and then from those extrapolate their results for the entire genome. Today, however, we have the majority of the human genome sequences, practically all of which have been released and made public. This allows scientists to compare every single nucleotide base pair between humans and primates—something that was not possible prior to the human genome project. In January 2002, a study was published in which scientists had constructed and analyzed a first-generation human chimpanzee comparative genomic map. This study compared the alignments of 77,461 chimpanzee bacterial artificial chromosome (BAC) end sequences to human genomic sequences. Fujiyama and colleagues “detected candidate positions, including two clusters on human chromosome 21, that suggest large, nonrandom regions of differences between the two genomes” (2002, 295:131). In other words, the comparison revealed some “large” differences between the genomes of chimps and humans.
Amazingly, the authors found that only 48.6% of the whole human genome matched chimpanzee nucleotide sequences. [Only 4.8% of the human Y chromosome could be matched to chimpanzee sequences.] This study compared the alignments of 77,461 chimpanzee sequences to human genomic sequences obtained from public databases. Of these, 36,940 end sequences were unable to be mapped to the human genome (295:131). Almost 15,000 of those sequences that did not match human sequences were speculated to “correspond to unsequenced human regions or are from chimpanzee regions that have diverged substantially from humans or did not match for other unknown reasons” (295:132). While the authors noted that the quality and usefulness of the map should “increasingly improve as the finishing of the human genome sequence proceeds” (295:134), the data already support what creationists have said for years—the 98-99% figure representing DNA similarity is grossly misleading, as revealed in a study carried out by Roy Britten of the California Institute of Technology (see Britten, 2002).
Exactly how misleading came to light in an article—“Jumbled DNA Separates Chimps and Humans”—published in the October 25, 2002 issue of Science. The first three sentences of the article, written by Elizabeth Pennisi (a staff writer for Science), represented a “that was then, this is now” type of admission of defeat. She wrote:
For almost 30 years, researchers have asserted that the DNA of humans and chimps is at least 98.5% identical. Now research reported here last week at the American Society for Human Genetics meeting suggests that the two primate genomes might not be quite as similar after all. A closer look has uncovered nips and tucks of homologous sections of DNA that weren’t noticed in previous studies (298:719, emp. added).
Genomicists Kelly Frazer and David Cox of Perlegen Sciences in Mountain View, California, along with geneticists Evan Eichler and Devin Locke of Case Western University in Cleveland, Ohio, compared human and chimp DNA, and discovered a wide range of insertions and deletions (anywhere from between 200 bases to 10,000 bases). Cox commented: “The implications could be profound, because such genetic hiccups could disable entire genes, possibly explaining why our closest cousin seems so distant” (as quoted in Pennisi, 298:721).
Britten analyzed chimp and human genomes with a customized computer program. To quote Pennisi’s article:
He compared 779,000 bases of chimp DNA with the sequences of the human genome, both found in the public repository GenBank. Single-base changes accounted for 1.4% of the differences between the human and chimp genomes, and insertions and deletions accounted for an additional 3.4%, he reported in the 15 October [2002] Proceedings of the National Academy of Sciences. Locke’s and Frazer’s groups didn’t commit to any new estimates of the similarity between the species, but both agree that the previously accepted 98.5% mark is too high (298:721, emp. added).
While Locke’s and Frazer’s team was unwilling to commit to any new estimate of the similarity between chimps and humans, Britten was not. In fact, he titled his article in the October 15, 2002 Proceedings of the National Academy of Sciences, “Divergence between Samples of Chimpanzee and Human DNA Sequences is 5%” (Britten, 99:13633-13635). In the abstract accompanying the article, he wrote: “The conclusion is that 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” (99:13633, emp. added). The news service at NewScientist.com reported the event as follows:
It has long been held that we share 98.5 per cent of our genetic material with our closest relatives. That now appears to be wrong. In fact, we share less than 95 per cent of our genetic material, a three-fold increase in the variation between us and chimps.
The new value came to light when Roy Britten of the California Institute of Technology became suspicious about the 98.5 per cent figure. Ironically, that number was originally derived from a technique that Britten himself developed decades ago at Caltech with colleague Dave Kohne. By measuring the temperature at which matching DNA of two species comes apart, you can work out how different they are.
But the technique only picks up a particular type of variation, called a single base substitution. These occur whenever a single “letter” differs in corresponding strands of DNA from the two species.
But there are two other major types of variation that the previous analyses ignored. “Insertions” occur whenever a whole section of DNA appears in one species but not in the corresponding strand of the other. Likewise, “deletions” mean that a piece of DNA is missing from one species.
Together, they are termed “indels,” and Britten seized his chance to evaluate the true variation between the two species when stretches of chimp DNA were recently published on the internet by teams from the Baylor College of Medicine in Houston, Texas, and from the University of Oklahoma.
When Britten compared five stretches of chimp DNA with the corresponding pieces of human DNA, he found that single base substitutions accounted for a difference of 1.4 per cent, very close to the expected figure.
But he also found that the DNA of both species was littered with indels. His comparisons revealed that they add around another 4.0 per cent to the genetic differences (see Coghlan, 2002, emp. added).
It seems that, as time passes and scientific studies increase, humans appear to be less like chimps after all. In a separate study, Barbulescu and colleagues also uncovered another major difference in the genomes of primates and humans. In their article “A HERV-K Provirus in Chimpanzees, Bonobos, and Gorillas, but not Humans,” the authors wrote: “These observations provide very strong evidence that, for some fraction of the genome, chimpanzees, bonobos, and gorillas are more closely related to each other than they are to humans” (2001, 11:779, emp. added). The data from these results go squarely against what evolutionists have contended for decades—that chimpanzees are closer genetically to humans than they are to gorillas. Another study using interspecies representational difference analysis (RDA) between humans and gorillas revealed gorilla-specific DNA sequences (Toder, et al., 2001)—that is, gorillas possess sequences of DNA that are not found in humans. The authors of this study suggested that sequences found in gorillas but not humans “could represent either ancient sequences that got lost in other species, such as human and orang-utan, or, more likely, recent sequences which evolved or originated specifically in the gorilla genome” (9:431).
The differences between chimpanzees and humans are not limited to genomic variances. In 1998, a structural difference between the cell surfaces of humans and apes was detected. After studying tissues and blood samples from the great apes, and sixty humans from various ethnic groups, Muchmore and colleagues discovered that human cells are missing a particular form of sialic acid (a type of sugar) found in all other mammals (1998, 107[2]:187). This sialic acid molecule is found on the surface of every cell in the body, and is thought to carry out multiple cellular tasks. This seemingly “miniscule” difference can have far-reaching effects, and might explain why surgeons were unable to transplant chimp organs into humans in the 1960s. With this in mind, we never should declare, with a simple wave of the hand, “chimps are almost identical to us” simply because of a large genetic overlap.
CONCLUSION
Homology (or similarity) does not prove common ancestry. The entire genome of the tiny nematode (Caenorhabditis elegans) also has been sequenced as a tangential study to the human genome project. Of the 5,000 best-known human genes, 75% have matches in the worm (see “A Tiny Worm Challenges Evolution”
. Does this mean that we are 75% identical to a nematode worm? Just because living creatures share some genes with humans does not mean there is a linear ancestry. Biologist John Randall admitted this when he wrote:
The older textbooks on evolution make much of the idea of homology, pointing out the obvious resemblances between the skeletons of the limbs of different animals. Thus the “pentadactyl” [five bone—BH/BT] limb pattern is found in the arm of a man, the wing of a bird, and flipper of a whale—and this is held to indicate their common origin. Now if these various structures were transmitted by the same gene couples, varied from time to time by mutations and acted upon by environmental selection, the theory would make good sense. Unfortunately this is not the case. Homologous organs are now known to be produced by totally different gene complexes in the different species. The concept of homology in terms of similar genes handed on from a common ancestor has broken down... (as quoted in Fix, 1984, p.189).
Yet textbooks and teachers still continue to proclaim that humans and chimps are 98% genetically identical. The evidence clearly demonstrates vast molecular differences—differences that can be attributed to the fact that humans, unlike animals, were created in the image and likeness of God (Genesis 1:26-27; see Lyons and Thompson, 2002a, 2002b). Elaine Morgan commented on this difference.
Considering the very close genetic relationship that has been established by comparison of biochemical properties of blood proteins, protein structure and DNA and immunological responses, the differences between a man and a chimpanzee are more astonishing than the resemblances. They include structural differences in the skeleton, the muscles, the skin, and the brain; differences in posture associated with a unique method of locomotion; differences in social organization; and finally the acquisition of speech and tool-using, together with the dramatic increase in intellectual ability which has led scientists to name their own species Homo sapiens sapiens—wise wise man. During the period when these remarkable evolutionary changes were taking place, other closely related ape-like species changed only very slowly, and with far less remarkable results. It is hard to resist the conclusion that something must have happened to the ancestors of Homo sapiens which did not happen to the ancestors of gorillas and chimpanzees (1989, pp. 17-18, emp. added).
Apologetics Press - Do Human and Chimpanzee DNA Indicate an Evolutionary Relationship?
REAL GENOMIC DIFFERENCES
One of the downfalls of previous molecular genetic studies has been the limit at which chimpanzees and humans could be compared accurately. Scientists often would use only 30 or 40 known proteins or nucleic acid sequences, and then from those extrapolate their results for the entire genome. Today, however, we have the majority of the human genome sequences, practically all of which have been released and made public. This allows scientists to compare every single nucleotide base pair between humans and primates—something that was not possible prior to the human genome project. In January 2002, a study was published in which scientists had constructed and analyzed a first-generation human chimpanzee comparative genomic map. This study compared the alignments of 77,461 chimpanzee bacterial artificial chromosome (BAC) end sequences to human genomic sequences. Fujiyama and colleagues “detected candidate positions, including two clusters on human chromosome 21, that suggest large, nonrandom regions of differences between the two genomes” (2002, 295:131). In other words, the comparison revealed some “large” differences between the genomes of chimps and humans.
Amazingly, the authors found that only 48.6% of the whole human genome matched chimpanzee nucleotide sequences. [Only 4.8% of the human Y chromosome could be matched to chimpanzee sequences.] This study compared the alignments of 77,461 chimpanzee sequences to human genomic sequences obtained from public databases. Of these, 36,940 end sequences were unable to be mapped to the human genome (295:131). Almost 15,000 of those sequences that did not match human sequences were speculated to “correspond to unsequenced human regions or are from chimpanzee regions that have diverged substantially from humans or did not match for other unknown reasons” (295:132). While the authors noted that the quality and usefulness of the map should “increasingly improve as the finishing of the human genome sequence proceeds” (295:134), the data already support what creationists have said for years—the 98-99% figure representing DNA similarity is grossly misleading, as revealed in a study carried out by Roy Britten of the California Institute of Technology (see Britten, 2002).
Exactly how misleading came to light in an article—“Jumbled DNA Separates Chimps and Humans”—published in the October 25, 2002 issue of Science. The first three sentences of the article, written by Elizabeth Pennisi (a staff writer for Science), represented a “that was then, this is now” type of admission of defeat. She wrote:
For almost 30 years, researchers have asserted that the DNA of humans and chimps is at least 98.5% identical. Now research reported here last week at the American Society for Human Genetics meeting suggests that the two primate genomes might not be quite as similar after all. A closer look has uncovered nips and tucks of homologous sections of DNA that weren’t noticed in previous studies (298:719, emp. added).
Genomicists Kelly Frazer and David Cox of Perlegen Sciences in Mountain View, California, along with geneticists Evan Eichler and Devin Locke of Case Western University in Cleveland, Ohio, compared human and chimp DNA, and discovered a wide range of insertions and deletions (anywhere from between 200 bases to 10,000 bases). Cox commented: “The implications could be profound, because such genetic hiccups could disable entire genes, possibly explaining why our closest cousin seems so distant” (as quoted in Pennisi, 298:721).
Britten analyzed chimp and human genomes with a customized computer program. To quote Pennisi’s article:
He compared 779,000 bases of chimp DNA with the sequences of the human genome, both found in the public repository GenBank. Single-base changes accounted for 1.4% of the differences between the human and chimp genomes, and insertions and deletions accounted for an additional 3.4%, he reported in the 15 October [2002] Proceedings of the National Academy of Sciences. Locke’s and Frazer’s groups didn’t commit to any new estimates of the similarity between the species, but both agree that the previously accepted 98.5% mark is too high (298:721, emp. added).
While Locke’s and Frazer’s team was unwilling to commit to any new estimate of the similarity between chimps and humans, Britten was not. In fact, he titled his article in the October 15, 2002 Proceedings of the National Academy of Sciences, “Divergence between Samples of Chimpanzee and Human DNA Sequences is 5%” (Britten, 99:13633-13635). In the abstract accompanying the article, he wrote: “The conclusion is that 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” (99:13633, emp. added). The news service at NewScientist.com reported the event as follows:
It has long been held that we share 98.5 per cent of our genetic material with our closest relatives. That now appears to be wrong. In fact, we share less than 95 per cent of our genetic material, a three-fold increase in the variation between us and chimps.
The new value came to light when Roy Britten of the California Institute of Technology became suspicious about the 98.5 per cent figure. Ironically, that number was originally derived from a technique that Britten himself developed decades ago at Caltech with colleague Dave Kohne. By measuring the temperature at which matching DNA of two species comes apart, you can work out how different they are.
But the technique only picks up a particular type of variation, called a single base substitution. These occur whenever a single “letter” differs in corresponding strands of DNA from the two species.
But there are two other major types of variation that the previous analyses ignored. “Insertions” occur whenever a whole section of DNA appears in one species but not in the corresponding strand of the other. Likewise, “deletions” mean that a piece of DNA is missing from one species.
Together, they are termed “indels,” and Britten seized his chance to evaluate the true variation between the two species when stretches of chimp DNA were recently published on the internet by teams from the Baylor College of Medicine in Houston, Texas, and from the University of Oklahoma.
When Britten compared five stretches of chimp DNA with the corresponding pieces of human DNA, he found that single base substitutions accounted for a difference of 1.4 per cent, very close to the expected figure.
But he also found that the DNA of both species was littered with indels. His comparisons revealed that they add around another 4.0 per cent to the genetic differences (see Coghlan, 2002, emp. added).
It seems that, as time passes and scientific studies increase, humans appear to be less like chimps after all. In a separate study, Barbulescu and colleagues also uncovered another major difference in the genomes of primates and humans. In their article “A HERV-K Provirus in Chimpanzees, Bonobos, and Gorillas, but not Humans,” the authors wrote: “These observations provide very strong evidence that, for some fraction of the genome, chimpanzees, bonobos, and gorillas are more closely related to each other than they are to humans” (2001, 11:779, emp. added). The data from these results go squarely against what evolutionists have contended for decades—that chimpanzees are closer genetically to humans than they are to gorillas. Another study using interspecies representational difference analysis (RDA) between humans and gorillas revealed gorilla-specific DNA sequences (Toder, et al., 2001)—that is, gorillas possess sequences of DNA that are not found in humans. The authors of this study suggested that sequences found in gorillas but not humans “could represent either ancient sequences that got lost in other species, such as human and orang-utan, or, more likely, recent sequences which evolved or originated specifically in the gorilla genome” (9:431).
The differences between chimpanzees and humans are not limited to genomic variances. In 1998, a structural difference between the cell surfaces of humans and apes was detected. After studying tissues and blood samples from the great apes, and sixty humans from various ethnic groups, Muchmore and colleagues discovered that human cells are missing a particular form of sialic acid (a type of sugar) found in all other mammals (1998, 107[2]:187). This sialic acid molecule is found on the surface of every cell in the body, and is thought to carry out multiple cellular tasks. This seemingly “miniscule” difference can have far-reaching effects, and might explain why surgeons were unable to transplant chimp organs into humans in the 1960s. With this in mind, we never should declare, with a simple wave of the hand, “chimps are almost identical to us” simply because of a large genetic overlap.
CONCLUSION
Homology (or similarity) does not prove common ancestry. The entire genome of the tiny nematode (Caenorhabditis elegans) also has been sequenced as a tangential study to the human genome project. Of the 5,000 best-known human genes, 75% have matches in the worm (see “A Tiny Worm Challenges Evolution”
. Does this mean that we are 75% identical to a nematode worm? Just because living creatures share some genes with humans does not mean there is a linear ancestry. Biologist John Randall admitted this when he wrote: The older textbooks on evolution make much of the idea of homology, pointing out the obvious resemblances between the skeletons of the limbs of different animals. Thus the “pentadactyl” [five bone—BH/BT] limb pattern is found in the arm of a man, the wing of a bird, and flipper of a whale—and this is held to indicate their common origin. Now if these various structures were transmitted by the same gene couples, varied from time to time by mutations and acted upon by environmental selection, the theory would make good sense. Unfortunately this is not the case. Homologous organs are now known to be produced by totally different gene complexes in the different species. The concept of homology in terms of similar genes handed on from a common ancestor has broken down... (as quoted in Fix, 1984, p.189).
Yet textbooks and teachers still continue to proclaim that humans and chimps are 98% genetically identical. The evidence clearly demonstrates vast molecular differences—differences that can be attributed to the fact that humans, unlike animals, were created in the image and likeness of God (Genesis 1:26-27; see Lyons and Thompson, 2002a, 2002b). Elaine Morgan commented on this difference.
Considering the very close genetic relationship that has been established by comparison of biochemical properties of blood proteins, protein structure and DNA and immunological responses, the differences between a man and a chimpanzee are more astonishing than the resemblances. They include structural differences in the skeleton, the muscles, the skin, and the brain; differences in posture associated with a unique method of locomotion; differences in social organization; and finally the acquisition of speech and tool-using, together with the dramatic increase in intellectual ability which has led scientists to name their own species Homo sapiens sapiens—wise wise man. During the period when these remarkable evolutionary changes were taking place, other closely related ape-like species changed only very slowly, and with far less remarkable results. It is hard to resist the conclusion that something must have happened to the ancestors of Homo sapiens which did not happen to the ancestors of gorillas and chimpanzees (1989, pp. 17-18, emp. added).
Apologetics Press - Do Human and Chimpanzee DNA Indicate an Evolutionary Relationship?
