Friday, September 14, 2012

When is a Mistake Not a Mistake?

Writing science journalism is hard, and is bound to include mistakes, but even the mistakes are illuminating. The act of condensing and translating complicated science invariably lets in half-truths and downright errors that spell out hidden assumptions. I undoubtedly made a few in this article. So mistakes are not always simply mistakes, if they still let the truth in through the cracks.

One such mistake I'd like to point out involves the term mistake. (Hopefully I can write this without creating an infinite regression of self-referentiality a la Douglas Hofstadter.) The headline reads 
"500-Million-Year-Old 'Mistake' Led to Humans." The article describes an organism without a backbone that is ancestor to all organisms with backbones. Right before the backbone appeared, the genome doubled, not once, but twice. Now there were four copies of every protein, so that one copy could keep doing its protein thing but the other three could gradually start doing something else and the organism would survive. In the sense of now having four genes instead of one, there is more "space" for the proteins to try to do new things and pick up new attributes. This expanded genomic space allowed new signaling networks of dozens of proteins to evolve. Ultimately, a backbone resulted because of the duplicated proteins.

This is a great example of how creation-by-evolution doesn't have to take small steps. It can take big steps -- a whole genome duplicated, twice! -- and then can move forward from there. Whole systems can duplicate, and that redundancy is like having a computer backup of files. The old files are still there, and then the new files can change. If the system crashes, bring out the old files. If the system works better, keep the new files and charge on ahead.

Unfortunately it's also a great example of how assumptions can color headlines. The doubling is repeatedly referred to as a "mistake" in the news story, and by the original scientists. Kind of funny that a mistake could happen twice in quick succession like that. It starts to look like a pattern, as in "Fool me once, shame on you; fool me twice, shame on me." Sure, the doubling could have been brought on by a random event, if that's what they mean by mistake. But in a community of organisms even unlikely random events are bound to happen. Someone's going to win the lottery, somewhere, eventually, and someone's going to get a backbone.

More than that, the "mistake" terminology neglects the possibility that genome doubling events may actually be intentionally regulated by the organism. Maybe it meant to do that! This is the main thrust of Shapiro's Evolution: A View From the 21st Century (my review here), that regulation plays a role in evolution. Shapiro documents cases where environmental stress causes genome remodeling, specifically mentioning that organisms can undergo genome duplications deliberately (more precisely, as a response to conditions). The increased "space" for genes to change and morph that results in changes in the organism is an amazing thing, and a lot of words could be used to describe it, but the best word for it is clearly not the word "mistake."

Ultimately, the real damage is done to the people who may have otherwise read that article who turned away as soon as they saw the word "mistake." I used to be one of those people, and it was science journalism like this that actually got in the way of my understanding the science, because it jumped to the conclusion that something is a mistake simply because we don't entirely understand it. That's a philosophical conclusion, not a scientific one. And, yes, it's a mistake.

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