afdave
Posts: 1621
Joined: April 2006
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Good morning everyone--
We are getting close to wrapping up this thread and I feel it is an important thread because the differences between apes and humans are in fact immense, and whether you realize it or not, there are many major issues riding on the answer to the question, "Common Descent or Common Design?"
The bottom line, of course, is ...
IF Common Descent is true, then there is no need for a Creator. Humans are free to believe in one, or pretend there is one, or whatever. None of the 'God talk' really matters much and those who don't care to participate in 'God think' are free to leave 'Him' completely out of their thoughts and discussions. There is no afterlife, no heaven, no ####, no judgment for actions in this life, and the best we can do is live in harmony with our fellow man and have a good time until we die. And when we die, that's the end of the story.
However, IF Common Design is true, then this raises a whole string of potentially life changing questions. What is this Designer like? Is it one Designer? Or many? If He designed ME, does he want anything from me? The Creation myths are well known ... could there be any truth to any of them? After all, there is one in particular that speaks of a Creator God who will someday hold humans accountable for their actions. Could there be any truth to this? Could it be that the Creator God spoken of in the Bible might in fact be one and the same as the Designer of the Cosmos and Biological Systems for which evidence continues to mount?
I think it was Renier (can't remember for sure) who said that he "used to be a YEC fundy" but is no longer because of the Vitamin C issue.
Just to recap yesterday ... Talk Origins has two relevant articles that I found
(1) Plagiarized Errors and Molecular Genetics
Another argument in the evolution-creation controversy
by Edward E. Max, M.D., Ph.D.
and
(2) 29+ Evidences for Macroevolution, Part 2: Past History
Copyright © 1999-2004 by Douglas Theobald, Ph.D.
Prediction 2.3: Molecular vestigial characters
Abstracts for the 3 articles referred to by the second article are as follows:
| Quote | Abstracts from Talk Origins: 29+ Evidences - Vitamin C Pseudogene
1: J Biol Chem. 1992 Oct 25;267(30):21967-72. Related Articles, Links
Guinea pigs possess a highly mutated gene for L-gulono-gamma-lactone oxidase, the key enzyme for L-ascorbic acid biosynthesis missing in this species.
Nishikimi M, Kawai T, Yagi K.
Institute of Applied Biochemistry, Yagi Memorial Park, Gifu, Japan.
Guinea pigs cannot synthesize L-ascorbic acid because of their deficiency in L-gulono-gamma-lactone oxidase, a key enzyme for the biosynthesis of this vitamin in higher animals. In this study we isolated the L-gulono-gamma-lactone oxidase gene of the rat and the homologue of this gene of the guinea pig by screening rat and guinea pig genomic DNA libraries in lambda phage vectors, respectively, using a rat L-gulono-gamma-lactone oxidase cDNA as a probe. Sequencing analysis showed that the amino acid sequence of the rat enzyme is encoded by 12 exons and that all the intron/exon boundaries follow the GT/AG rule. On the other hand, regions corresponding to exons I and V were not identified in the guinea pig L-gulono-gamma-lactone oxidase gene homologue. Other defects found in this gene homologue are a deletion of the nucleotide sequence corresponding to a 3' 84-base pair part of rat exon VI, a 2-base pair deletion in the remaining exon VI-related region, and nonconformance to the GT/AG rule at one of the putative intron/exon boundaries. Furthermore, a large number of mutations were found in the amino acid-coding regions of the guinea pig sequence; more than half of them lead to nonconservative amino acid changes, and there are three stop codons as well. Thus it is clear that the guinea pig homologue of the L-gulono-gamma-lactone oxidase gene exists as a pseudogene that randomly accumulated a large number of mutations without functional constraint since the gene ceased to be active during evolution. On the basis of the neutral theory of evolution, the date of the loss of L-gulono-gamma-lactone oxidase in the ancestors of the guinea pig was roughly calculated to be less than 20 million years ago.
J Biol Chem. 1994 May 6;269(18):13685-8. Related Articles, Links
Cloning and chromosomal mapping of the human nonfunctional gene for L-gulono-gamma-lactone oxidase, the enzyme for L-ascorbic acid biosynthesis missing in man.
Nishikimi M, Fukuyama R, Minoshima S, Shimizu N, Yagi K.
Institute of Applied Biochemistry, Yagi Memorial Park, Gifu, Japan.
Man is among the exceptional higher animals that are unable to synthesize L-ascorbic acid because of their deficiency in L-gulono-gamma-lactone oxidase, the enzyme catalyzing the terminal step in L-ascorbic acid biosynthesis. In the present study, we isolated a segment of the nonfunctional L-gulono-gamma-lactone oxidase gene from a human genomic library, and mapped it on chromosome 8p21.1 by spot blot hybridization using flow-sorted human chromosomes and fluorescence in situ hybridization. Sequencing analysis indicated that the isolated segment represented a 3'-part of the gene, where the regions corresponding to exons VII, IX, X, and XII of the rat L-gulono-gamma-lactone oxidase gene remain with probable deletion of the regions corresponding to exons VIII and XI. In the identified exon regions were found various anomalous nucleotide changes, such as deletion and insertion of nucleotide(s) and nonconformance to the GT/AG rule at intron/exon boundaries. When the conceptual amino acid sequences deduced from the four exon sequences were compared with the corresponding rat sequences, there were a large number of nonconservative substitutions and also two stop codons. These findings indicate that the human nonfunctional L-gulono-gamma-lactone oxidase gene has accumulated a large number of mutations without selective pressure since it ceased to function during evolution.
Biochimica Biophysica Acta, International Journal of Biochemistry and Biophysics,(ISSN: 00063002) 1999 Oct 18;1472(1-2):408-11. Related Articles, Links
Random nucleotide substitutions in primate nonfunctional gene for L-gulono-gamma-lactone oxidase, the missing enzyme in L-ascorbic acid biosynthesis.
Ohta Y, Nishikimi M.
Department of Biochemistry, Wakayama Medical College, Japan.
Humans and other primates have no functional gene for L-gulono-gamma-lactone oxidase that catalyzes the last step of L-ascorbic acid biosynthesis. The 164-nucleotide sequence of exon X of the gene was compared among human, chimpanzee, orangutan, and macaque, and it was found that nucleotide substitutions had occurred at random throughout the sequence with a single nucleotide deletion, indicating that the primate L-gulono-gamma-lactone oxidase genes are a typical example of pseudogene. |
The first article above compares the functional rat GLO gene with the supposedly homologous guinea pig GLO gene and finds significant differences. They say "Thus it is clear that the guinea pig homologue of the L-gulono-gamma-lactone oxidase gene exists as a pseudogene that randomly accumulated a large number of mutations without functional constraint since the gene ceased to be active during evolution."
The second article does the same comparison for rats and humans and concludes ... "These findings indicate that the human nonfunctional L-gulono-gamma-lactone oxidase gene has accumulated a large number of mutations without selective pressure since it ceased to function during evolution."
The third article does the same comparison among humans, chimpanzees, orangutans, and macaques, and it was found that "nucleotide substitutions had occurred at random throughout the sequence with a single nucleotide deletion, indicating that the primate L-gulono-gamma-lactone oxidase genes are a typical example of pseudogene."
Dr. Max draws on these findings and compares the situation to a copyright court case. His argument is that since apes and humans have the same "errors" in the "broken GLO gene", this shows that apes and humans have a common ancestor.
Now this has one HUGE assumption which appears to me to be entirely unwarranted. now maybe it is warranted, but no one gave me any reasons that it should be yesterday
DR. MAX's HUGE ASSUMPTION
The apparently homologous "GLO gene" in humans, primates and guinea pigs used to function to produce Vitamin C, but now no longer does. As such this constitutes a "broken gene" caused by random mutation. My question is ... why do you assume these 3 organisms EVER had a functioning GLO gene? Maybe this gene DOES HAVE a function which we just don't know about. After all, we are seeing a dramatic reversal in the area of pseudogenes. Scientists are all of a sudden finding all kinds of purpose for them. Do a Google Scholar search to see this.
Does anyone have any good arguments for why this is a good assumption to make?
Because Dr. Max's whole argument rests on this being a valid assumption. If it is not valid, then his whole argument fails.
OK ... now tell me ... why is this assumption valid?
(By the way, Tom Ames, I didn't see that frame shift mutations have anything to do with this discussion, but please correct me if I am wrong)
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A DILEMMA FOR THE COMMITTED NATURALIST
A Hi-tech alien spaceship lands on earth ... DESIGNED.
A Hi-tech alien rotary motor found in a cell ... NOT DESIGNED.
http://afdave.wordpress.com/....ess.com
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It was also *conceivable* that the scene had been designed by a known intelligent agency, perhaps to film a movie or destract authorities from a heist or... But in my silly scientific fashion, I observed all I could and applied parsimony in the analysis. Whoops. 
