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Biting Commentary about Infinity, and Beyond!

« Hindsight, Twenty Twenty (Take Two) | Main | Space Cowboys »

A Touch Of Toxin

There's an old saying that there are no poisons per se--only toxic doses. Many things that are toxic in large quantities can be harmless, even beneficial, in small ones (which is why the Delaney Clause--the federal mandate requiring products to be banned if they cause cancer in lab mice in any quantities, is absurd). Now, we have another example of it, that may have staggering scientific consequences.

Ultra-violet light is often used to kill micro-organisms, so as a major component of sunlight, it's always been seen as an impediment to the development of life on a young earth. But now researchers have found that it may, under some circumstances, actually contribute to building organic links, and may have contributed to the early development of replicating systems.

Posted by Rand Simberg at May 29, 2003 04:56 PM
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Delaney Clause
Excerpt: Good Lord. If you want to hear some scientific insanity, read about the Delaney Clause, which seeks to ban any product found to cause cancer...
Weblog: Dean's World
Tracked: May 30, 2003 12:04 AM
Comments

Interesting article. One of the things I like about basic scientific research is that it has the effect of nullifying bigotries... eventually.

I also find that when something is true, things just seem to fall into place. More and more pieces just seem to fit. Circles inside circles vs. Keplers elliptical orbits is a model example.

That doesn't seem to be the case here. To overcome the RNA/DNA chicken and egg, naturally the simpler RNA is the focus, simpler being very relative. The article includes a number of sleight of hand tricks that could easily be overlooked for someone intent on reaching an evolutionary conclusion. A few points:

1) It doesn't say RNA is immune to the destructive nature of UV, only that one of three components is more effecient at absorbing UV. The sugar and phosphate components of RNA degrade under UV, where the article strongly suggests (simply by not mentioning it) that they would not because they are protected. I wonder what would happen to their computer model if the computer itself were subjected to sufficiently strong UV for a period of time? It wouldn't need to be geological time either!

2) RNA is much more likely to form long chains than other organic molecules. So what's the absolute probability? Instead of no chance at all, we have 1 over the age of the universe? What is it?

3) Now we jump to UV being the natural selector - so somehow all that UV is no longer an obstacle.

4) Then we propose that UV replace those electrical sparks as the energy source for change. Again removing these delicate chemicals immediately from the source of this supposed force of life. They do mention split seconds.

Hey, maybe that's how it all worked, but it still seems like circles within circles to me. Perhaps they imagine they can stretch them enough to produce ellipses?

Posted by ken anthony at May 29, 2003 05:49 PM

BTW, I agree with you completely that the 'Delaney Clause' if it's as you state, is complete absurd.

Posted by ken anthony at May 29, 2003 05:53 PM

Rand: the Delaney Clause article you linked to is from 1996. Do we know that this clause is still in effect? Have you got any references on that?

Dean

Posted by Dean Esmay at May 31, 2003 01:12 AM

Ken, I think you misunderstand what the article has said. For one, your "absolute probability" statement appears to assume that there is exactly one RNA complex available on the entire young Earth -- whereas there would more likely be molar quantities of suitable precursors, even in relatively small geographical areas. There needn't be an especially high rate of success when a) the successful molecules reproduce, and b) there are 10^n (where n is not a small number) simultaneous experiments proceeding in parallel.

Next, UV is the selector -- so the impact of UV is very naturally reduced on those UV-resistant "survivors". What's so hard to understand about that?

And finally, chemical reactions (including polymerization) do typically take place in "split seconds"; I'm not sure what your criticism of their statement is supposed to mean...

Posted by Troy at May 31, 2003 01:52 AM

I don't know for sure, Dean, but I don't recall hearing that it had been revoked. It's possible that it was, though, since it was what did in saccharine, and I think that's available again.

I wasn't necessarily complaining about it as a current artifact of law (and it was actually put into force back in the fifties)--I was just pointing out the absurdity of the general principle, because many still subscribe to it.

Posted by Rand Simberg at May 31, 2003 10:12 AM

I think you mean cyclamates. Saccharine is still with us, but cyclamates are still banned--although they shouldn't be.

You're right about the general attitude it reveals though. But I've got a friend ragging all over me about this now becuase we discovered the article is so old. Of course he also went apes**** when I pointed out the fact that arsenic is a nutrient, so what are you gonna do?

Posted by Dean Esmay at May 31, 2003 02:11 PM

Troy,

I did find the article interesting and appreciate that Rand takes the time to bring such things to our attention. It's one of the reasons I enjoy visiting his blog.

I personally feel that where humans are concerned there is no such thing as unbias, we all have our axes to grind. So an article that may seem objective or balanced to one may not to another. In this case, and perhaps unfairly, I thought some of the things unsaid were worth commenting upon.

As to your 3 points...
Regardless of the process that produces it, we may reasonably say that at some point RNA exists and before that time did not. The article itself implies that, it's kind of the point. However a single strand or a trillion is immaterial and I implied neither. What I did say in other words is that saying something is more likely than another is missing the point if the absolute probability is nil in any case.

Perhaps you are assuming that molar quantities of likely precursors self-evidently assumes they must result in RNA? I would think you could stop the presses with that one. Saying something is likely does not constitute proof, does it? On the contrary, UV is demonstratably destructive even to the components (precursors?) of RNA.

I'll give you the second point, certainly UV could be described as a selector. I'll let the second part of my third statement stand for itself.

You are right that I was unclear with regard to my mention of split seconds. From the article...

'There is a small probability that RNA bases hit by UV light may be energised for a split second to a state where they can chemically react with another molecule to form another link in the chain'

My comment wasn't really about the split second itself, rather it had to do with what would be happening immediately after should this small probability have occured. Which is that if left exposed to the UV there would be a very large probability of degradation that would completely overwhelm any small probability of the event occuring. I think that's a rather important point to have been left out.

I'd like to think that the standards for scientific articles was something better than you might expect from the NY...Times! But perhaps I'm just an idealist?

Still, the main thrust of the article about UV resistance was interesting.

Posted by ken anthony at June 1, 2003 11:37 PM

Perhaps it would help if mentioned why I thought the article was interesting? Being an INTJ, I like to understand the meaning of thing free of bigotry or prejudice. Anyone familier with Meyer-Briggs would know that INTJ's are natural scientists. My mind is full of all those powerful childlike questions that others have long since dismissed.

So when I read an article that says RNA has some resistance to UV, I don't think about some conjectured old soup, I think about UV hitting living things today, right now. It seems to me that kind of resistance might have practical application to living things and I wonder what it would mean to living things today if that resistant didn't exist.

This childlike wonder at the world can lead to some powerful insights.

So how far does UV penetrate a body (a few layers of skin or more?)

What would the impact be without this resistance?

Personally, I think these are very interesting questions.

Posted by ken anthony at June 2, 2003 09:15 AM


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