Wednesday, September 23, 2009

Unintelligent Design

I'm taking some biology classes, thinking about applying to some grad programs. I'm learning a lot - mostly cellular biology right now. But the more I learn, the more obvious it becomes that life was not intelligently designed. It's really hard to believe anyone who has more than a tenuous grasp on basic biology can believe in ID, especially that the IDer was the all powerful, all omniscient God. Vestigial organs, vestigial genes, and tons of other obvious design flaws litter the biological landscape. I'll talk about RNA transcription next time. First, I'll tell you about the crazy hack embedded in our DNA replication.


(I've gotten kind of technical, and I've tried to keep it short, so please do email me if you don't understand something, and I'll try to update the post to make it more readable.)

Updates posted on Oct 6 follow the original post.


Telomeres are what is known in the software design world as a "hack" - a quick and dirty fix to a bug or design flaw. To understand telomeres, you have to know a little about DNA and DNA replication. (I've attempted a terse explanation here, but there's always Wikipedia for a more thorough description.) A single strand of the DNA double helix consists of a string of nucleotides. These nucleotides contain the familiar A, C, G and T bases that are held by 5-carbon sugar rings, and the rings are connected by phosphate groups. These sugars are not symmetrical. They have an oxygen atom in one part of the ring, and a carbon atom sticking off the side. Biologists have labeled the carbons 1 - 5. The 3' carbon and the 5' carbon are the two that bond to the phosphate group, and to make a strand of DNA, you have to keep all the nucleotide lined up the same way: 3' - 5' - phosphate - 3' - 5' - phosphate and so on.


The problem is, the enzymes that assemble new DNA strands can only add nucleotides to the 3' end, not the 5' end. I'm not going to go into it here, but that causes an ugly little work-around called Okazaki fragments during the normal part of DNA replication. Where the real problem happens is at the ends of the DNA strand. You end up with a little bit that's too close to the end of the template to code on. If you could add to the 5' end, it wouldn't be a problem because you could work backwards from that end, but since you can only add to the 3' end, and you don't have the room to work there, you end up losing a little bit of your DNA every time it replicates.

The hideous hack we use to get around this is, whenever you make a gamete (sperm or egg) a special enzyme adds telomeres - non-coding nonsense DNA - to the ends of all of your chromosomes, so that as they fall off, it won't eat into your genes... until your cells have replicated for a bunch of years. When humans were only living into their 40s, this wasn't so much of a problem. Now, this might be one of the causes of aging. Your cells are losing their instruction manuals page by page, each time they divide.

There are two obvious fixes that an intelligent designer could have used. As previously mentioned, she could have engineered an enzyme that could add to the 5' end of the DNA. This would solve two problems and make your DNA replication much more efficient, both in time and energy consumption. The second fix is already used by bacteria. She could have stored the DNA in long rings, or just connected the ends during the final steps of replication. Bacteria store parts of their DNA in little rings, and those rings don't have the problem because they can build the last part of their DNA off the place where they started. I don't know how making a ring out of our DNA would affect chromosome storage, but you wouldn't have to keep it in a ring all the time. We have enzymes in our cells that cut DNA apart and paste it back together, so the rings could just be connected during the last parts of DNA replication. An intelligent designer would have been able to see these options and make the choice. Evolution blindly fumbled around for whatever worked, and we ended up with telomeres.



Update: Check out this short video of DNA replication:



Update:
On Oct 5, Nobel Prize for Physiology or Medicine was given to three scientists for their work finding telomeres and telomerase - the enzyme that creats them. From the press release
Elizabeth Blackburn and Jack Szostak discovered that a unique DNA sequence in the telomeres protects the chromosomes from degradation. Carol Greider and Elizabeth Blackburn identified telomerase, the enzyme that makes telomere DNA. These discoveries explained how the ends of the chromosomes are protected by the telomeres and that they are built by telomerase.
And to complete this amazing coincidence of my writing this post and telomeres turning up in the international press, at least one prominent ID promoter has claimed telomeres as support for ID. In an article DLH posted on Uncommon Descent:
These telomeres can probably be shown to be essential to survival, and are likely to be irreducibly complex. If so, how can macro evolution explain the origin of this marvelous preservation feature that appears to be an Intelligent Design?
Gonna do some research to show that they're irreducibly complex? Nope. Gonna do a little googling and find out that there are other, arguably better ways to solve the problem that telomeres fix? Nope. IDiot..

Go to Sandwalk for another explanation of what telomeres are, why we need them, etc. from a Professor of Biochemistry.

9 comments:

Kyle P. said...

You tease. You string us along with little tidbits and then wham, you pull out the Okazaki fragments and make us that much more curious.

The standard theist response is, "How do you KNOW they don't have a function?" But the answer to that is that we don't need to know that they don't have a function - it's enough to know that there's a much better alternative that could have been done. Then they say, "How do you know that your alternative is better?" I don't know how to answer that one.

John said...

Actually, the standard response from the theists I know (i.e. my mom and here sisters) is "I don't have to understand, I just have to believe."

"It's really hard to believe anyone who has more than a tenuous grasp on basic biology can believe in ID, especially that the IDer was the all powerful, all omniscient God."

Well, I doubt most bleevers know much molecular biology. What passed for biology when I was in High School stopped at gross descriptions of cellular events. If you explain it to them, they typically ignore you. I am cynical enough to think that the creationist leaders do know it's all a steaming load.

h said...

Thanks for this simplified explanation of how this applies to ID (or rather does NOT apply to ID :). As a formerly, brainwashed Christian, I have a lifetime of fact ignoring to overcome, and so I (sadly) need the concepts spoon-fed to me atm. Not to worry. I am starting to get up to speed on the theory of evolution now that I am not afraid to go to hell for peaking at the evidence for it, and should be up-to-speed shortly.

Jackie said...

Kyle,

To answer your second question: the ring DNA would be far more energy efficient, and it isn't used up like telomeres are.

John,

I knew a born-again Christian who was doing a biology minor in college. I don't remember if he finished; I know the molecular stuff was hard for him. But I thought he was generally a smart guy, perfectly capable of reasoning, so it was to believe he could rationalize the way he did. On top of that, he was a Psych major, so he knew all about rationalization, compartmentalization and cognitive dissonance.

h,

It's a real shame that you were indoctrinated like that. Lying for Jesus - to children - it makes me sick! But it's great that you're taking the steps to reeducate yourself now. Keep it up!

Intelligent Designer said...

I think that you have jumped to the conclusion that there is no intelligent designer when you could have concluded that the intelligent designer(s) are not omniscient nor omnipotent.

I assume you are a software developer like myself. If so your have probably looked back at some of you old code and thought of better ways to do it. Did you then come to the conclusion that you don't exist?

Jackie said...

There might be a fringe of people who believe we were designed by intelligent aliens, but someone who actually believes that shows up, I am not going to waste my time countering that extremely unpopular POV. The overwhelming majority of ID proponents are creationists. It is their brand of intelligent design that I am providing evidence against.

BTW, if I hired you to engineer some molecular biology, and you created telomeres or the Eukaryotic polymerase, I would definitely label your design choices "unintelligent."

Kyle P. said...

To add to Jackie's point, if you exist outside of time, then you wouldn't even be able to write bad code, then go back at it and see that you could have written better. The whole concept is corrupt.

marie said...

I'm educated in Biology and I believe in God.

By trying to disprove the existence of some type of God, aren't you implying that you believe there is some God? Because how can you disprove something that doesn't exist?

Jackie said...

Marie said: "Because how can you disprove something that doesn't exist?"

You can ONLY disprove the existence of that which does not exist. Study logic or advanced math sometime. The concept of that which you are disproving must exist, but not the thing itself.

I'm not trying to prove that the sentence "God exists" doesn't exist. I'm providing evidence that the sentence is false. And this post is by no way a disproof - it's just evidence against the existence of the typical creationist's god.