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In Light of New BIO-Complexity Paper, Maintaining Neo-Darwinism Means Rejecting Established Methods of Historical Science

Casey Luskin

biologic2headerimageshadowcompress.jpgIn the new BIO-Complexity paper, “Enzyme Families-Shared Evolutionary History or Shared Design? A Study of the GABA-Aminotransferase Family,” Mariclair Reeves, Ann Gauger, and Douglas Axe find that modern enzymes cannot be easily mutated to acquire new functions. One 2009 study that their paper cites states, “[M]any attempts at interchanging activities in mechanistically diverse superfamilies have since been attempted, but few successes have been realized.” This suggests that modern enzymes are not amenable to evolutionary conversions.

The typical response from evolutionists is that perhaps ancient enzymes were different, and more readily mutable to acquire new functions. Perhaps so. However, as Reeves, Gauger, and Axe explain, this means evolutionary scientists must then ignore experimental evidence showing that protein conversions require many mutations.

That would reveal Darwinism as being grounded in speculation instead of experimental data. In their new paper they write:

We are asking whether the enzymes now present in life are as amenable to functional conversion as ancient enzymes must have been in order for evolution to work. If the answer to this is No, then the classical recruitment scenario does not work today, anyway. That realization would be of considerable importance, in that it would call for careful consideration of how processes that do not work today somehow did work long ago. In other words, it would reinforce the importance of grounding evolutionary explanations in observable science.

The same rejoinder might be offered to defenders of the “promiscuity” hypothesis of protein evolution. According to this model, perhaps ancient enzymes performed many functions. Then, over time some of those functions may have been lost and others finely tuned, leading to today’s enzymes which perform specific functions extraordinarily well. Do modern enzymes show the kind of promiscuity that ancient enzymes supposedly needed? That’s not clear. Moreover, this model relies upon loss of function to explain enzyme specificity, and never accounts for the origin of new enzyme functions in the first place. Reeves, Gauger, and Axe continue:

This idea of functional divergence from promiscuous ancestral enzymes, though possibly of some value, leaves the most fundamental aspects of the origins question unchanged. Whether ancient enzymes resembled modern ones closely or only loosely, the modern ones are both the things to be explained and the things we can observe. The importance of grounding evolutionary explanations in actual study of modern enzymes therefore remains as important now as ever. Yet the promiscuity hypothesis leaves the actual origin of new enzyme functions unexplained. In the end, then, functional conversion by mutation is still the only evolutionary explanation for those first appearances.

As we saw previously, their experimental data suggests that many mutations — including deleterious ones — would be necessary to generate new protein functions. It would take enormously long periods of time — longer than the age of the earth — to generate the mutations needed for new protein functions. When the experimental data conflicts with the predictions of the theory, what is a Darwinian to do?

The answer is they ignore the experimental data. They assume that biological systems in the past could evolve because they worked very differently than they do today. This is not a scientific form of reasoning. It’s a dictated not by the evidence but by faith in the overall Darwinian doctrine.

We saw the same kind of thing when UC Berkeley paleontologist Charles Marshall debated Discovery Institute’s Stephen Meyer in 2013 on the origin of new biological information. A point that emerged was that Marshall simply pushed back the question of the origin of new information. He ignored the evidence showing that modern developmental gene regulatory networks (dGRNs) don’t tolerate mutations, making it very difficult to evolve new body plans. When you mutate developmental gene regulatory networks, the organism dies. In response to Meyer, Marshall argued that perhaps in the past, dGRNs were more plastic than they are today, thereby allowing new body plans to evolve. Meyer explained in rebuttal that Marshall had stopped using uniformitarian reasoning:

Marshall and other defenders of evolutionary theory reverse the epistemological priority of the historical scientific method as pioneered by Charles Lyell, Charles Darwin and others. Rather than treating our present experimentally based knowledge as the key to evaluating the plausibility of theories about the past, Marshall uses an evolutionary assumption about what must have happened in the past (transmutation) to justify disregarding experimental observations of what does, and does not, occur in biological systems. The requirements of evolutionary doctrine thus trump our observations about how nature and living organisms actually behave. What we know best from observation takes a back seat to prior beliefs about how life must have arisen.

In light of the experimental data from Biologic Institute, much the same could be said of proponents of the co-option model of protein evolution. As Meyer artfully put it, those who simply assume that ancient enzymes were more amenable to evolutionary conversions “reverse the epistemological priority of the historical scientific method.” Evolutionists are welcome to ignore the experimentally derived real-world workings of modern biology if that’s what they want to do, but they should acknowledge that they are asking for special treatment for their theory. In defense of Darwinism, they have departed from the established methods of historical science.

Casey Luskin

Associate Director, Center for Science and Culture
Casey Luskin is a geologist and an attorney with graduate degrees in science and law, giving him expertise in both the scientific and legal dimensions of the debate over evolution. He earned his PhD in Geology from the University of Johannesburg, and BS and MS degrees in Earth Sciences from the University of California, San Diego, where he studied evolution extensively at both the graduate and undergraduate levels. His law degree is from the University of San Diego, where he focused his studies on First Amendment law, education law, and environmental law.