Genetic Brethren? Considering Homology

Take a look in the mirror and study the features of your face. Are you looking at the face of a monkey? Though perhaps not quite as dramatic, evolutionists propose that humans and chimpanzees share a common ancestor and thus share common traits. Because man and chimp have similar physical and genetic characteristics, it is generally regarded as support for an evolutionary understanding of origins and ancestry within secular academia. But is that the end of the story? Homology and origins have a much deeper tale to tell than what is popularized in the school textbooks, and the conclusions favor the biblical description of Creation and history.
 
 

 Homology and the Human Genome
 
 Homology describes “traits inherited by two organisms from a common ancestor"(1). In regards to evolutionary arguments of chimpanzees being man's closest relative, studies most specifically cite similarities anatomically and genetically. Such speculation has been popularized by the completion of the Human Genome Project. The project began in 1990 and was completed in 2003 with the goals to identify all the genes in human DNA and determine what makes humans human (2). What did the scientists working on the project find? Researchers discovered the 3.2 billion nucleotide base pairs in human DNA, realized that all people share 99.9% the same human genome sequence, and much more (3). As a result of the project, a number of books have been published with research on the genomes in a number of plants and animals, including that of the chimpanzee.
 
Before the mapping of the human genome, evolutionists commonly used physical similarities to support their arguments that humans and chimps are distant cousins. After the Human Genome Project was completed, however, evolutionists boldly proclaimed the research as evidence for evolution. Why? The similarities in the DNA sequences between humans and chimpanzees is so close that they have to share common ancestors, according to evolutionists. Originally, the human genetic similarity to chimpanzees was believed to be about 98.5%. Further research suggested that humans and chimpanzees, genetically, are 95% similar, however (4). Why the discrepancy? Because original calculations refused to account for a number of differences between humans chimpanzees, such as chromosome count (humans have 23, chimps 24), telomere (the end of the chromosome) length, and others (5). In addition, less than 1% of the entire genome was studied to develop the numbers (6). More-so, previous studies omitted “indels” (areas of the genome with no sequence homology) from their final calculations, distorting the data conclusions.

Studies in recent publications are suggesting that the 95% similarly is quite lower, in fact. Upon further research that was published in a secular journal, 5.4 Mb (million bases) within human sequences were not found in chimpanzee chromosome 22. Including some generous assumptions of the homologous nature of the two genetic sequences, this actually suggests a homology of less than 90%. Why's that a big deal? Dr. Daniel Chriswell, molecular biologist at the Institute for Creation Research, explains:

If the human and chimpanzee genomes are 10% different, it rules out the possibility that humans and chimpanzees evolved from a common ancestor. If the difference between the two genomes is 10% then the total number of differences in the DNA sequence would be approximately 300 million nucleotide bases (10% of 3 billion nucleotides present in humans or chimpanzees), meaning that 150 million bases in both the human and chimpanzee have mutated and been fixed in the population since the last common ancestor. If the hypothetical divergence of humans and chimpanzees occurred about 5 million years ago and given that a human generation is about 20 years (and a chimp slightly less), then 250,000 generations have passed from the time humans and chimpanzees diverged from a common ancestor. To get 150 million nucleotide changes in 250,000 generations, the two lines of descent would require 600 beneficial mutations fixed in each population of ancestral humans and chimpanzee per generation. However, nearly all mutations are neutral, having no effect and therefore are not selectable, or are slightly deleterious, causing genetic deterioration in a population of organisms. A few beneficial mutations have been observed, such as mutations that confer antibiotic resistance in bacteria and sickle cell trait in humans. But even these mutations are deleterious when the individual is returned to optimal conditions for survival and forced to compete with other individuals lacking the mutation. Recognizing the high genetic cost of fixing any mutation in a population, J.B.S. Haldane, an evolutionist, determined mathematically that it would take 6 million years to fix just 1,000 beneficial mutations in humans through natural selection. If only 1,000 of the mutations are beneficial, then nearly all of the 150 million mutations in the human lineage would be slightly deleterious or neutral. Deleterious mutations would lead to degeneration of the genome resulting in extinction, and the neutral mutations would cause no change. This does not lead to some "great leap forward" to a more adapted creature. Because there is no feasible evolutionary solution to this problem, this whole situation has been termed 'Haldane's dilemma.' Even if the difference in homology of humans and chimpanzees is just 98.5% there still would be 250,000 beneficial mutations to be fixed in both populations in the last 5 million years, far too many than are feasible by Haldane's calculations." (7)

Even if the genome sequences are 95-96% similar, as the broad, secular consensus maintains, the numbers are quite deceiving. 1.23% of the differences represents roughly 35 million differences, and when one considers the 40-45 million bases found in humans but not in chimps (and, in addition, vice versa), that number grows to around 125 million differences. To recap, there are about 35 million different DNA bases between chimps and humans, approximately 45 million DNA bases found in humans and not in chimpanzees, and around 45 million DNA bases found in chimpanzees and not in humans. That's a lot of differences, and a lot of problems for evolutionary homology enthusiasts. (8)

I Like The Way You Talk

Sequence similarity does not guarantee similarity in function. Consider the FOXP2 protein. This protein is important for language, and contains just 2 out of 700 amino acids which are different between human and chimpanzee genomes. Doing the math, that puts the similarity of the FOXP2 protein between humans and chimpanzees at a remarkable 99.7%. Ever try holding a conversation with a chimp? Though the influential language protein is so genetically similar between both kinds, it is clear that they serve different purposes (or are being carried out in much different ways). In fact, closer examination has shown just a couple of amino acid changes at specific positions that directly affect the output of the protein. (9)

Reaching Across the Aisle *

A natural question arises when talking about such complexities as the human genome: Are we genetically similar to any other organisms? Due to the popularity of Darwinism, chimpanzees seem to get all the credit. Actually humans are quite similar to quite a few different kinds of animals, a few of which are quite surprising (specifically if you're coming from an evolutionary perspective).

Some of the data found upon research of genomes discovered that humans had many genetic markers that were more similar to gorillas than that of chimpanzees. 18-29% of the genetic markers (“a DNA sequence with a known physical location on a chromosome" (10)) contained within the study of human, gorilla, and chimpanzee genomes actually matched closer together than direct matches between humans and chimps – weakening the common claim that chimpanzees and humans undeniably share a common ancestor. (11)

It starts to become real interesting when one examines human similarity to non-primates, however. Mice and men share more in common than the name of a famous novel. One article that appeared in the popular science journal Nature provides some telling details:

The 2.5-Gb mouse genome sequence ... from the C57BL/6J strain, reveals about 30,000 genes, with 99% having direct counterparts in humans... Humans appear to have about the same number of genes, with similar sequence, and we both like cheese." (12)

The Human Genome Project's government web-page also notes the differences actually lie “in the structure of genes and the activities of their protein products”, though “Gene for gene, we are very similar to mice." (13)

Cats are remarkably similar to a number of mammals, particularly humans. Significantly, cats have 90% homologous genes with humans. Check out the full table here.

Without straying too far from our monkey friends, it is also surprising to note how closely humans are related to a banana. As the website “Making the Modern World” explains, “Even the DNA of plants is similar to that of humans. We share 60% of our DNA with a banana." (14)

None of this suggests (nor is anyone suggesting) that humans and cats or bananas share direct, common ancestors. But it does pose an important question: if homology doesn't guarantee common ancestry between humans, mice, and bananas, why do evolutionists insist that homology between humans and chimpanzees guarantee common ancestors? Like the FOXP2 protein responsible for language, sequence similarity is not the same as function similarity. Homology is a weak argument for evolutionists, and is deceptive in its reliance on percentages (as shown with the comparative studies of humans to other organisms).


Last year, an article in Nature rocked the scientific community. The piece, “Chimpanzees and human Y chromosomes are remarkably divergent in structure gene content”, countered many of the claims of human and chimpanzee similarity in DNA. As the Institute for Creation Research notes, the original studies of chimpanzee genome sequence back in 2005 were based upon maps of the human genome instead of the chimpanzee genome. In general size, the chimpanzee genome is around 10% larger than the human genome, and thus skewed original beliefs of human and chimpanzee homology based on practical and philosophical (bias towards evolutionary presuppositions) flaws. The new mapping, which the recent article in Nature refers to, was based upon a Y-chromosome map for chimps, not humans. Why's that a big deal? Because the chimpanzee's DNA sequence can actually be compared to the human's DNA sequence on its own ground, providing a much more accurate picture of contrast between the two genomes. (15)

What did they find? The Institute for Creation Research's Brian Thomas and Jeffery Tomkins state that “the human and chimp Y chromosomes were constructed entirely differently. On the human Y chromosome, there were found four major categories of DNA sequence that occupy specific regions. One can think of this in terms of geography. Just as a continent like Europe is divided into countries because of different people groups, so are chromosomes with different categories of DNA sequence.” And there's more: (16)

Not only were the locations of DNA categories completely different between human and chimp, but so were their proportions. One sequence class, or category containing DNA with a characteristic sequence, within the chimpanzee Y chromosome had less than 10 percent similarity with the same class in the human Y chromosome, and vice versa.... (17)

[T]he chimp was lacking approximately half of the genes found on a human Y chromosome. Because genes occur in families or similarity categories, the researchers also sought to determine if there was any difference in actual gene categories. They found a shocking 33 percent difference. The human Y chromosome contains a third more gene categories--entirely different classes of genes--compared to chimps... (18)

When all aspects of non-similarity--sequence categories, genes, gene families, and gene position--are taken into account, it is safe to say that the overall similarity was lower than 70 percent.” (19)

Obviously, chimpanzee DNA sequences yield much different results when based upon chimpanzee Y-chromosomes instead of human Y-chromosomes. The results are about as cut and dry as Thomas and Tomkins remakring: “the human Y chromosome looks just as different from a chimp as the other human chromosomes do from a chicken” (20). The great contrast from the previous study to the new one has impressed and shocked many scientists. R. Scott Hawley of the Stowers Institute in Kansas City called the results “astounding” (21). Geneticist Huntington Willard of Duke University was more blunt: “Just when we thought we were getting the sense that we had a pretty good picture of what our genome is like and how it evolved, we get tossed this curve ball” (22).

Common Ancestry or Common Designer?

Despite claims that humans and chimpanzees share common ancestors, continual research in homology and genomics are beginning to suggest otherwise. Though original assertions that humans and chimps were just 2% different in terms of DNA sequence, recent studies have proven that percentage to have increased to a conservative estimate of 30%. When one considers just how many base pair differences that actually is, the absurdity of the belief that humans and chimpanzees evolved from a common ancestor becomes increasingly evident. In addition, homologous chromosomes have also proven not to equate to homologous function.

Though DNA similarity between humans, mice, cats, and bananas may sound shocking, it isn't all that surprising when one considers how the Bible's description of origins differs from the evolutionary dogma which encompasses modern academia today. Scripture is clear: God created the heavens and the earth (with all life on it) around 6,000 years ago. More-so, He created all life according to their created kinds. Man and chimp are not products of the same great-grandfather primate that lived millions of years ago. Instead, they are distinct creatures created for different and beautiful purposes.


Sources:

1) “Similarities and differences: understanding homology and analogy”. Understanding Evolution. Berkely. Online. Accessed 11 Jun. 2011. a href="http://evolution.berkeley.edu/evolibrary/article/similarity_hs_01%3E">http://evolution.berkeley.edu/evolibrary/article/similarity_hs_01>;.
2) “About the Human Genome Project”. Human Genome Project Information. Genomics.energy.gov. 19 Aug. 2008. Online. Accessed 11 Jun. 2011. a href="http://www.ornl.gov/sci/techresources/Human_Genome/project/about.shtml%3E">http://www.ornl.gov/sci/techresources/Human_Genome/project/about.sh...;.
3) “Insights Learned from the Human DNA Sequence”. Human Genome Project Information. Genomics.energy.gov. 9 Oct. 2009. Online. Accessed 11 Jun. 2011. a href="http://www.ornl.gov/sci/techresources/Human_Genome/project/journals/insights.shtml%3E">http://www.ornl.gov/sci/techresources/Human_Genome/project/journals...;.
4) Britten, Roy J. Divergence between samples of chimpanzee and human DNA sequences is.... PNAS. 22 Aug. 2002. Online. Accessed 11 Jun. 2011. a href="http://www.pnas.org/content/99/21/13633.abstract%3E">http://www.pnas.org/content/99/21/13633.abstract>;.
5) DeWitt, David. “Greater than 98% Chimp/human DNA similarity? Not any more.” Answers in Genesis. Apr. 2003. Online. Accessed 11 Jun. 2011. a href="http://www.answersingenesis.org/tj/v17/i1/DNA.asp%3E">http://www.answersingenesis.org/tj/v17/i1/DNA.asp>;.
6) Ibid.
7) Criswell, Daniel. “Genomics at ICR”. Institute for Creation Research. Online. Accessed 11 Jun. 2011. a href="http://www.icr.org/article/genomics-at-icr/%3E">http://www.icr.org/article/genomics-at-icr/>;.
8) DeWitt, David. “What About the Similarity Between Human and Chimp DNA?” The New Answers Book 3. Green Forest: Master Books, 2010. Print.
9) Ibid.
10) “Genetic Marker”. National Human Genome Research Institute. Online. Accessed 14 Jun. 2011. a href="http://www.genome.gov/glossary/?id=86%3E">http://www.genome.gov/glossary/?id=86>;.
11) Ibid Source 8.
12) Gunter, Chris & Dhand, Ritu. “The Mouse Genome”. Nature 420, 509. 5 Dec. 2002. Online. Accessed 14 Jun. 2011. a href="http://www.nature.com/nature/journal/v420/n6915/full/420509a.html%3E">http://www.nature.com/nature/journal/v420/n6915/full/420509a.html>;.
13) Stubbs, Lisa. “Functional and Comparative Genomics Fact Sheet”. Human Genome Project Information. Genomics.energy.gov. 17 May 2011. Online. Accessed 14 Jun. 2011. a href="http://www.ornl.gov/sci/techresources/Human_Genome/faq/compgen.shtml#stubbs%3E">http://www.ornl.gov/sci/techresources/Human_Genome/faq/compgen.shtm...;.

14) “What is Life? The Double Helix”. Making the Modern World. 2004. Online. Accessed 14 Jun. 2011. a href="http://www.makingthemodernworld.org.uk/stories/defiant_modernism/01.ST.02/?scene=6&tv=true%3E">http://www.makingthemodernworld.org.uk/stories/defiant_modernism/01...;.
15) Tomkins, Jeffery & Thomas, Brian. “New Chromosome Research Undermines Human-Chimp Similarity Claims”. Institute for Creation Research. 2010. Online. Accessed 14 Jun. 2011. a href="http://www.icr.org/article/5292/%3E">http://www.icr.org/article/5292/>;.
16) Ibid
17) Ibid.
18) Ibid.
19) Ibid.
20) Ibid.
21) Qtd in: Borenstein, Seth. “Men More Evolved? Y Chromosome Study Stirs Debate”. US News. 13 Jan. 2010. Online. Accessed 14 Jun. 2011. a href="http://www.usnews.com/science/articles/2010/01/13/men-more-evolved-y-chromosome-study-stirs-debate%3E">http://www.usnews.com/science/articles/2010/01/13/men-more-evolved-...;.
22) Qtd in: Y Chromosome Is and Evolutionary 'Hot Spot'”. Softpedia. 15 Jan. 2010. Online. Accessed 14 Jun. 2011. a href="http://news.softpedia.com/news/Y-Chromosome-Is-an-Evolutionary-Hot-Spot-132171.shtml%3E">http://news.softpedia.com/news/Y-Chromosome-Is-an-Evolutionary-Hot-...;.

* Thanks to this article for reference to many of the quotes in the section "Reaching Across the Aisle": Hodges, Mark. “Of Mice and Men, and Bananas”. Nontmanynoble Blog. 2 Apr. 2010. Online. Accessed 14 Jun. 2011. a href="http://notmanynoble.wordpress.com/2010/04/02/of-mice-and-men-and-bananas/%3E">http://notmanynoble.wordpress.com/2010/04/02/of-mice-and-men-and-ba...;.

 


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Comment by Private Private on July 1, 2011 at 5:30pm

Very nice post, thank you very much.

 

Going to a public highschool, Biology classes brainwash students that just because there are some aspects in the structure between humans and chimpanzees are similar, we share a common ancestor. Like you mentioned though, if we evolved from chimps, then the Nucleotide base pairs would not be so dramatically different. Also as you said, because we share 60% of our DNA with bananas, it does not mean that we share common ancestors with bananas. 

 

In Christ,

Private (I don't use my real name.)

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