by Greg Krehbiel on 19 February 2012
If you listen to the rhetoric on the so-called “science blogs,” you’re a heretic, a creationist and a moron if you so much as question the idea that random mutation provides sufficient material for natural selection to bring about the kind of evolutionary changes we see in the fossil record. (At least that’s how it seems to me.)
If someone were to say, “I don’t think random mutation is enough to get the job done. The odds are just too small.” Wouldn’t it be reasonable for a scientist to say, “It’s possible you’re right. There are other sources of genetic variation that we know of, and there might be more we haven’t discovered yet.”
But that’s not what usually happens. The idea that some other force may be necessary to provide the required changes is mocked and scorned. This is not because anybody has proven that random mutation does all the work. (How could they?) It’s simply because they’re scared to death that opening the door to some other factor may leave room for that guy upstairs.
The reaction prompts religious people to think that what’s really going on here isn’t science, but hatred of God. And they have a point. It often seems that’s the real motivation. But the similar reaction against any hint of Lamarchism undercuts that argument. It seems it’s really more of a “circle the wagons” kind of thing. Probably combined with poor social skills.
I find the Spanish Inquisition-like reactions self-defeating and unscientific. The first step in the quest for knowledge is to say “I don’t know.” Insisting that random mutation is good enough, and there’s no need to look for any other mechanisms, is at least as counterproductive as that cartoon where the guy inserts “then a miracle occurs” in his equation.
How do we know that the environment never affects heritable characteristics? How could we possibly know it?
The truth is that scientists have not ignored the possibility of other mechanisms. What I see repeatedly is that when they’re talking about science, they’re open to other ideas. Maybe the environment can affect heritable traits. Maybe the randomness of mutations goes beyond stuff like transcription errors. Sometimes other weird things are going on, like horizontal gene transfer.
I don’t pretend to understand everything being discussed in this article — A Biochemical Mechanism for Nonrandom Mutations and Evolution — but it’s clear that the author is trying to understand what’s going on, not trying to Defend Doctrine.
In the last couple decades some really cool stuff has surfaced. As you might expect, life is far more interesting and complicated than we thought. I’m convinced that in the next decade or two we’ll find mechanisms going on in our DNA that make all the theories from 30 years ago seem like medieval nonsense.
It seems inevitable. Scientists used to regard cells as little more than puddles of goo in a balloon. They had no concept of transcription errors, recombination, repair, or any of the stuff that’s common knowledge today, including the incredible molecular machinery. Scientists are only beginning to understand all the wacky stuff that goes on in there. I think it’s very unlikely that the old theories will remain unchanged.
Which is one of the reasons I have a hard time reading the science blogs. They need to add a double espresso dose of intellectual humility to their daily routine.
-- 2012-02-19 » Greg Krehbiel