Vitamin C

 

Scurvy, Vitamin C and Common Ancestry

 

Do you accept the humans and apes have a common ancestor?

If not, explain why chimpanzees and humans share the same defective gene.

 

 

by Iain » Sun Aug 27, 2006 4:11 am

Vitamin C (Ascorbic Acid) is a vital requirement in our diet and to our survival. If we don't get it we get scurvy. Scurvy was a common problem when sailors used to sail for months with no fruit or vegetables

Most mammals synthesise vitamin C: they do not need to get vitamin C in their diet as we do. They have enzymes in place to synthesize it. When we look at the human genome we find that the gene for creating one of these enzymes has a major defect right in the middle of it. Because of this defect we cannot produce Vitamin C. If you look at the genome of some of our other closely related primates, chimpanzees and gorillas etc. they also have the same defective Gene. The position of this defective gene in the various ape species statistically correlates with the exact same position in each genome so this was not an accident in each separate genome. It therefore follows that this defective gene or mutation arose in the common ancestor that led to this branch of apes. The fact that we are not able to produce our own vitamin C has not been much of a problem in the past because there has always been adequate fruit and vegetables available.

 

In case anyone is confused about what a common ancester is maybe this diagram will help.

 

 

by spongebob » Sun Aug 27, 2006 8:35 am

There's no doubt that humans and other apes (we are just one form of "ape") have common ancestors. Although the proof requires some understanding of science, which probably accounts for the dissention amongst most of the ultra-religious who are not scientists. It is easy to reject notions you don't understand.

Very good article, Iain, and I liked the diagram as well.

 

 

by narsil » Sun Aug 27, 2006 7:28 pm

good stuff, and quite interesting actually, but I'll give you the quick and easy way out of that really convincing a (creationist) theist.

When you see...

Image

Image Image



...you imediately know who did those, he didn't start from ground zero everytime, they have commonality: the colors, the paints, the strokes especially. Anything we have in common with other animals: two eyes, a nose, skin, needing iron, oxygen-based blood, whatever, doesn't imply neccessarily that we come from the same place, just that we were made with the same parts. Now your example is a bit more technical than two eyes, but I'm just trying to explain to you the other side and why it's less strong of an argument than you might think.

 

 

by spongebob » Sun Aug 27, 2006 8:31 pm

Narsil, those are very pretty pictures, but not much of an argument. Are you asserting that god intentionally placed identical markers, such as the aforementioned damaged gene as well as pseudogenes, retroviruses and identical versions of functionally-redundant proteins in the DNA of humans and chimps for reasons we cannot ascertain? Understand that these similarities have nothing at all to do with how we function. Monkeys get along fine with the old gene. To suggest such a thing is to suggest that god has intentionally misled us. Knowing we would eventually dig deep enough to find these markers, god would know what the obvious conclusion would be.

you imediately know who did those, he didn't start from ground zero everytime, they have commonality: the colors, the paints, the strokes especially. Anything we have in common with other animals: two eyes, a nose, skin, needing iron, oxygen-based blood, whatever, doesn't imply neccessarily that we come from the same place, just that we were made with the same parts. Now your example is a bit more technical than two eyes, but I'm just trying to explain to you the other side and why its less strong of an argument than you might think.



It's interesting that you acknowledge the more obvious commonalities humans have to other mammals, Narsil. But what of the invertebrates? What of plants? All those genetic markers correctly confirm the predictions made by evolutionary theory long ago, that we humans are more closely related to apes than squid.

And to accurately portray your analogy of painting to the tree of life, you would have to go much broader. Yes, all these were created by Van Gogh with paint and canvas and they do show similarities. And if one were to study his painting at the microscopic level, one would likely see the similarities in stroke. But nowhere would one see a trait that was carried through generations of his work that appeared in some paintings, but not others (the analogy being one group of related works and another group not related to the first). This is what we see with evolution of the species, groups of related creatures that have common traits and other groups that have their own set of common traits not shared by the first group. The obvious reason is shard hereditiy. You don't doubt that you got your physical attributes from your parents and that you passed on some of those traits to your offspring, do you?

So this isn't a valid argument against common ancestry. It's nonsense.

 

"Religion is something left over from the infancy of our intelligence, it will fade away as we adopt reason and science as our guidelines."


by Iain » Mon Aug 28, 2006 8:45 am

Narsil, At least you gave a response even though it's lacking as SB has pointed out. The point I am making is not technical or difficult to understand so theists can't get out of that door. The point is quite simple.

Everyone accepts that our genome carries the information that defines us from generation to generation.

Humans and some apes cannot produce their own Vitamin C because of a defective gene. The defective sequence in the gene is in the same position in the genomes it affects.

Most other Mammals can produce their own Vitamin C and do not have this defective gene.

So if you believe God created us why did he decide to give a defective gene to just humans and some apes?

In this forum in the past several of us have directed Christians to excellent sources to learn about evolution. Evolution 101 for example that highlights the irrefutable evidence for common ancestry and evolution within DNA in about six different areas. However, I don't think any of them ever went and listened to them. I suppose if they are going to get a major reason for their belief cut off why should they step up to the chopping block. This approach is really hiding from reality though. This thread has been viewed about 30 times, six have voted 'yes'. I know I have viewed it just to check on it about five times so there are a lot of people who have viewed it and decided not to state their view. Maybe I should have added an option of
 


I wish I'd never read this post, I don't want to know this information or think about it so I am going to ignore it and not vote.

 

The difference between science and religion is the difference between a willingness to dispassionately consider new evidence and new arguments and a passionate unwillingness to do so. - S.H.

by narsil » Mon Aug 28, 2006 12:33 pm

I was just trying to throw out there the great wall of defense against any arguments of that type. I'm not saying it's perfect, and I'm not saying that I completely buy it either, but just trying to inform you guys of a typical response. The common features suggesting a common source is actually quite compelling once you get down into genes and such, as opposed to say like water or something. I mean a cloud is 97% water, and so is a watermelon, but nobody thinks that watermelons come from clouds. It's a very interesting point. and the guy that figures out a gene therapy to fix that one such that we don't ever need our vitamins will make quite the load of dough. I'd be interested to see if processing that ourselves had any side effects.

by spongebob » Tue Aug 29, 2006 7:36 am

Thanks, Narsil. I'm pretty familiar with the typical Creationist responses. Partly because I have read and reread as much material on evolution as I could get my hands on, looking for areas where I might be mistaken. Everything I've read has only strengthened my understanding and acceptance of evolution. I find that the vast majority of Christians who reject evolution do so out of a misunderstanding of the theories and an intellectual barrier. They are not so much incapable of understanding, but are unwilling to seriously consider the technical aspects and evidence. I personally feel that it is a defense mechanism. They are truly afraid that if they ever open themselves up to evolution that it will eventually lead to a point where they will question their faith. Same goes for the geologic age of the earth and universe.

I once spoke to a very intelligent and charismatic high-ranking military officer. He was also a creationist who believed that god created the universe with age built right in, including light from the stars already at our doorstep and dinosaur fossils beneath our feet. I certainly can't refute this belief, no one can. But why would such an intelligent and rational person choose to buy into such an unnecessary model of creation? Why put god in the equation when it is clearly not needed? Why would his god so deceive us unless it is evil and enjoys torturing us?

by Iain » Tue Aug 29, 2006 7:50 am

narsil wrote: I was just trying to throw out there the great wall of defense against any arguments of that type. I'm not saying it's perfect, and I'm not saying that I completely buy it either, but just trying to inform you guys of a typical response. the common features suggesting a common source is actually quite compelling once you get down into genes and such, as opposed to say like water or something.

So you think that because some other things have common features and because they aren't linked this can apply to this, too? In the water example you give this is a very abundant molecule available in just about everything and arranged in no particular order. You are comparing it to a very distinctive occurrence, a tiny change within the instruction book to build a certain species

So are you are saying that a gene just happened to mutate in a few species of ape and they would have the same defect in the exact same gene in the same location and this was coincidence? Yet this didn't happen in the vast majority of other mammals. Actually the only other mammals known who also can't produce their own vitamin C is the guinea pig and a single species of bat. However the affected gene is in an entirely different location and the defect in a different position within the gene.

The argument they/you are making certainly isn't a great wall of defence. Its no argument at all.

Anyway the question is: You believe God created us, why would God make this very unusual distinctive defect? A defect that renders a number of genes completely useless causing the mechanism for producing vitamin C to fail. If you say it was because of the fall then why did he inflict the poor chimp and gorilla as well?

The other thing you could come up with is that chimps, gorillas orangutans, bonobos and us have a common ancestor: Adam and Eve and they lived 50,000,000 years ago. I don't think that will be too palatable either, though.

Linus Pauling who won 2 Nobel prizes believed that this defect in humans was the reason why we were so susceptible to the common cold. Mammals who are capable of making their own vitamin C produce it in quantities far greater than that needed to prevent scurvy. Pauling believed that if we take vitamin C in similar quantities it would prevent the cold and a lot of other ailments. However tests and trials carried out have not really borne this out but a lot of people still believe in taking high doses of Vitamin C. Some take it in small quantities as a multivitamin but I think it's pointless. So if gene therapy manages to fix this defect it may not bring any great improvement except in those who eat so little fruit and veg that they are borderline to getting scurvy.

 

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