Blue Collar Scientist

The Panda’s Thumb summarizes some discussion that is occurring on various science blogs lately, a result of a new instance of the old intelligent design creationist ignorance about junk DNA.

The discussion makes pretty clear that historically there have been two camps about the effect of evolution and selection on the genome. From my lay perspective, I’ve identified those camps as the “strict Darwinians” on the one hand, and the “neutralists” on the other. This is my own terminology - maybe I borrowed it from somewhere and it might just possibly mean something to an expert in the field - but it has been a convenient way for me to think about competing hypotheses in some of the sub-disciplines of evolution.

Strict Darwinists, to my mind, would not expect junk DNA to be conserved. If this hypothesis were true, junk DNA would be “rare” - although it is well to note that rare can mean different things to different people, and that what is considered “rare” to an evolutionary biologist might look common to a layperson.

The neutralists, to my mind, would say that since mutations are random, and since some of the genome is redundant, and since some mutations can destroy the ability of a gene to code for a protein, junk DNA should be “common.” One of the ideas here is that junk DNA is not necessarily maladaptive, and its presence wouldn’t necessarily be selected against.

This means, incidentally, that the concept of junk DNA is not Darwinian. And that in turn means that when intelligent design creationists use the term “Darwinian” when they mean “evolutionist,” they are either lying¹ or ignorant².

This is, in any case, a thumbnail view of how I’ve been explaining this issue to people who ask. (I don’t really concentrate on evolution in my instruction activities - I’m more of an astronomer than a biologist.) I’m glad to find some support and some additional clarity for this oversimplified way of explaining these issues in the current round of discussion.

1. And therefore you shouldn’t pay any attention to them [↩]
2. You shouldn’t pay any attention to them in that case either. [↩]

This entry was posted on Thursday, January 24th, 2008 at 10:56 am and is filed under education and public outreach, evolution. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.