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Monday, October 29, 2007

Session Two: Why is origin of life such a difficult problem?

Update 1: Don Wallar's presentation was excellent, once we got the equipment going. I sensed students came away with a clear understanding, as per below, of why origin of life is an inherently difficult problem, made all the more so by the discovery in the last decade of the error correction system in the genetic code.

Update 2 - news: Leslie Orgel, father of the RNA World origin of life theory, hasdied at 80 years of age.

If you are interested in, or taking, the Design or Chance? course at Carr Hall at U of T (Tuesday nights, 7:00 p.m.), here is some introductory material on why the origin of life is such a difficult problem.

On October 25, 2007, there was a most interesting little story in The New York Times, "55 'Origin of Life' Paper Is Retracted" by Cornelia Dean. It concerns an elderly scientist, Homer Jacobson, who decided to retract a paper he had published in 1955 on origin of life in American Scientist, "Information, Reproduction and the Origin of Life".

He retracted it, he says, because creationists were citing it as evidence that the origin of life might require divine intervention and because he found errors in it:
"Another assertion in the paper, about what would have had to occur simultaneously for living matter to arise, is just plain wrong, he said, adding, “It was a dumb mistake, but nobody ever caught me on it."

Given the amount of speculation one can find in the origin of life field, I don't think we should be surprised if no one caught him on it. But anyway,
... Dr. Jacobson’s retraction is in "the noblest tradition of science," Rosalind Reid, editor of American Scientist, wrote in its November-December issue, which has Dr. Jacobson’s letter.

His letter shows, Ms. Reid wrote, “the distinction between a scientist who cannot let error stand, no matter the embarrassment of public correction,” and people who “cling to dogma.”

Now, that's laying it on a bit thick because there is no evidence that Jacobson was subject to any embarrassment - or apprehended that he would be. Indeed, the public relations value of the exercise has been to distract attention from the real significance of the story: In all that time, a great deal has been learned about life, but life's origin is still shrouded in mystery, AND much that Jacobson and his colleagues assumed fifty-two years ago is doubted today.

A lawyer friend kindly sent round a note to the effect that the "dumb mistake" may not even have been a mistake, or not exactly anyway:
... the very concept of "retraction" is inapplicable here. A retraction is something the original author can do because he or she has discovered, by re-examining his/her original data or reasoning or mathematics, that it was flawed. That's not what happened here. Instead, we have a situation in which -- if we take the professor at face value -- later work by other people implies that the earlier work was wrong for some other reason. The proper action in such a case is not to "retract" a paper -- which is an effort to erase it from the record -- but to acknowledge it to have been in error, as revealed by later work. Such an acknowledgement is not a power unique to the author -- anyone can declare an older theory superceded by a later one.

Indeed, if Jacobson's explanations are taken at face value, hundreds of older origin of life papers will need retraction. We will need a Journal of Retracted Origin of Life Papers.

However, my friend doubts that Jacobson's "retraction" should be taken at face value, rather,
Even if it is wrong, it ought to remain on the public record. But by having its author not merely dsavow its superceded conclusions, but formally "retract" the paper, the effect is to wipe it out of history.

And that, of course, reveals that the true purpose of his action is to prevent people from even being able to say that he once stated these things.

Obviously, if the paper had revealed anything important, he'd get little thanks for retracting it.

Essentially, what makes origin of life a difficult problem is that the average cell is of supercomputer-like complexity. Even simple cells are complex.

That was a surprise. Nineteenth century scientists had expected cells to be simple. The electron microscope disabused their successors of any such idea.

But that in turn created a problem: There is no clear route from goo to you that could all just happen by random motions of particles in solution. And that clear route is what the origin of life researchers had been looking for. Many today feel it their duty to look only for such a route and no other. If that was not the route, they will be looking forever.

Both Fred Hoyle and Francis Crick seriously considered the idea that life originated elsewhere in the universe, and some argue for this view today. Crick even thought that intelligent aliens might have brught life here.

Don't misjudge Crick just because that sounds bizarre. To get some idea how speculative the whole field is, read this. Here's a quick look at some of the issues over the years.

The take home point is that the problem of How did life begin? differs in character from problems like Is there life on Mars? When we get to Mars, we'll find out the answer to the second question. It is fairly straightforward, after all. Either there is (or was) something we can reasonably call life on Mars or else there isn't/wasn't. The only problem is getting to Mars to find out. (Of course life on Mars would generate a host of other questions, but it is a fairly simple one in itself.)

Despite suggestns like Crick's, the quest for how life began is - for the most part - a quest to identify a plausible origin of life in the random movements or natural tendencies of pre-life chemicals. Can such an origin be found? If not, why not? Ad what are our other options?

I am certainly looking forward to the presentation by our guest Don Waller, from the Biosimilars program at Apotex.

Note: Origin of life researchers are not, strictly speaking, trying to find out exactly what happened. That may not be possible. They are looking for demonstrably plausible routes to the origin of life. It is somewhat like trying to determine how a prisoner escaped jail. Absent a video, we can't know for sure. But using clues, we can construct a scenario by which he could escape that accords with the evidence (and doesn't obviously contradict any clear evidence).

Go here for the update on Session One.

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