Jamie Bridgham, Sean Carroll and Joe Thornton of the University of Oregon decided it was high time someone discovered a Darwinian mechanim producing irreducible complexity, and so they set to work on the problem. From Thornton’s website:
Molecular evolution of hormones and their receptors
How did hormones and their diverse functions in humans and other animals evolve? We study the evolution of vertebrate steroid hormones — such as estrogen, testosterone, and the stress hormone cortisol — and the receptor proteins that mediate these hormones’ effects on the body’s cells. Our goal is to reveal the specific molecular events by which hormones and receptors diversified and evolved their specific partnerships. By combining techniques from statistical phylogenetics, molecular endocrinology, ancestral gene resurrection, and experimental evolution, we are characterizing receptor biodiversity across the animal kingdom, reconstructing the evolution of the family at the genetic level, and testing hypotheses about the functions of ancient genes. Our goal is to illustrate how a complex, tightly integrated molecular system — one which appears to be "irreducibly complex" - evolved by Darwinian processes hundreds of millions of years ago.
Higly interesting work, and their results were published in Science this week– along with a considerable amount of fanfare. The University of Oregon put out a press release:
And the New York Times picked up the story. It was going wonderfully, but there was one slight catch.
Note to potential researchers: if you want to falisify irreducible complexity, it helps to work with an irreducibly complex system.
Behe responded to the article, labeling it as "the lamest attempt yet to answer the challenge irreducible complexity poses for Darwinian evolution". According to him…
The bottom line of the study is this: the authors started with a protein which already had the ability to strongly interact with three kinds of steroid hormones (aldosterone, cortisol, and “DOC” [11-deoxycorticosterone]). After introducing several simple mutations the protein interacted much more weakly with all of those steroids. In other words, a pre-existing ability was decreased.
The authors (including Christoph Adami in his commentary) are conveniently defining “irreducible complexity” way, way down. I certainly would not classify their system as IC.
In conclusion, the results (and even the imagined-but-problematic scenario) are well within what an ID proponent already would think Darwinian processes could do, so they won’t affect our evaluation of the science. But it’s nice to know that Science magazine is thinking about us!
The fellows of the DI Center for Science and Culture have a more thorough analysis of "what went wrong" in Bridgham et al’s study here.
Perhaps the paper deserves a bit more careful analysis.
In the latest curious development, Joe Thornton seems to have decided he never meant to test irreducible complexity after all. Compare the cached and current versions of his webpage here and here. The quote above is from the original version.