Evolutionary biologist: 'Twist of fate' responsible for important human protein

In the ongoing debate between Darwinism and intelligent design, an evolutionary biologist has attributed the development of an important human protein to a “twist of fate” rather than the accepted Darwinian process.

Biologist Joseph Thornton of the University of Chicago traced the evolutionary trail of an ancient ancestor of the glucocorticoid receptor, the cellular receptor for the stress hormone cortisol, to find out how the protein’s random mutations over billions of years evolved into its modern-day function.“This very important protein exists only because of a twist of fate,” the professor of ecology, evolution, and human genetics concluded, rather than attributing the receptor’s function to Darwin’s theory of the survival of the fittest.

To figure out how the protein came to be, Thornton and his team tried to create a “resurrected” version of the protein as it existed in the evolutionary past. Without a time machine to find out exactly what that looked like, they used biochemical methods to generate thousands of alternate histories that could have proceeded from a starting point hundreds of millions of years prior. What they found was that the ancestral form needed two very specific mutations for the protein to arrive at its modern form. But those mutations are rare and offer no beneficial effect on the protein by themselves, meaning that if Darwin’s evolutionary process was strictly followed, the modern glucocorticoid receptor would never have come to be.

“If our results are general—and we think they probably are—then many of our body’s systems work as they do because of very unlikely chance events that happened in our deep evolutionary past,” Thornton said.

Lehigh University biochemist Michael Behe, an intelligent design proponent, has a different explanation as to how the unlikely events came to be: a designer. “Thornton himself—apparently a conventional Darwinist, and certainly no sympathizer with intelligent design—does not attribute the protein receptor’s new function to Darwinian processes,” Behe said. “Rather he ascribes it mostly to ‘historical contingency.’ That’s another way of saying dumb luck.”