August 16, 2007 | David F. Coppedge

Artificial Selection Is Not Natural Selection

From Nature1 comes this point to ponder:

Evolution has crafted thousands of enzymes that are efficient catalysts for a plethora of reactions.  Human attempts at enzyme design trail far behind, but may benefit from exploiting evolutionary tactics.

The subheading summarized a commentary by Michael P. Robertson and William G. Scott (UC Santa Cruz) on “directed evolution” experiments by Burkhard Seelig and Jack Szostak, reported in the same issue of Nature.2  The commentary began:

Chemical reactions in living organisms are catalysed by enzymes, the vast majority of which are proteins.  These finely tuned catalysts are the result of billions of years of evolution, and far surpass anything yet created by humans.  Indeed, our ability to design enzymes, on the basis of our knowledge of protein structure and reaction mechanisms, can most charitably be described as primitive.

Burkhard Seelig and Jack Szostak used an iterative selection process to yield useful enzymes, but did not claim this is how nature did it.  They had a goal: “product formation as the sole selection criterion,” they said, meaning they were watching for a match to an intelligently chosen standard.  Though they called this “directed evolution” and “selection,” it was clear that the scientists were doing the directing and selecting.  Yet the commentary by Robertson and Scott said this was just like nature did it:

Although proteins have won the fitness contest of natural selection to become the pre-eminent enzymes, billions of years ago life may have started with RNA enzymes – ribozymes – in a putative RNA world that pre-dated proteins and DNA.4  The RNA bond-forming (ligation) reaction is a favourite of those studying evolution from an RNA world, because it is presumed to be the crucial chemical step of RNA self-replication.  Szostak and fellow molecular biologist David Bartel were the first to isolate a ribozyme ligase, using artificial selection.  Their technique is the prototypical method for the in vitro evolution of ribozymes, and has been adapted for protein enzymes by Seelig and Szostak in the current study.

Artificial selection toward a goal, however, is very different from natural selection as conceived by Darwin.  Natural selection has no goal, no direction, no retained knowledge, and no reward.3  Even Darwin worried about his term natural selection, because it seemed to imply an intelligent selector.  He later acquiesced to Herbert Spencer’s term, survival of the fittest, as a better encapsulation of his idea.
    The confusion between artificial selection and natural selection continued to the end of the article, where Robertson and Scott said, “Designing a selection process that includes ground-state interactions (as Seelig and Szostak’s study does) and transition-state interactions (as the previous catalytic-antibody approaches did) might yield even better-designed enzymes.”


1Michael P. Robertson and William G. Scott, “News and Views: Biochemistry: Designer Enzymes,” Nature 448, 757-758 (16 August 2007) | doi:10.1038/448757a.
2Burkhard Seelig and Jack W. Szostak, “Selection and evolution of enzymes from a partially randomized non-catalytic scaffold,” Nature 448, 828-831 (16 August 2007) | doi:10.1038/nature06032.
3Survival cannot be considered a reward in Darwinism.  Reward implies a rewarder and a goal that a contestant strives for.  In the value-neutral, materialistic world of blind natural selection, nobody could care if an organism survives or not.  For these reasons, the commentators’ characterization of a “fitness contest” won by “evolutionary tactics” is misleading.
4For problems with the RNA World scenario for the origin of life, see the 07/11/2002 and 02/15/2007 entries.

Even a middle school biology teacher or an NCSE staff member would know this is not natural selection.  How can the premiere science journal in the world allow this egregious an example of the fallacy of equivocation to make it into print?  Happens all the time, folks.  If the logical inconsistency was obvious to you, you’re wiser than eggheads at UC Santa Cruz and the editors of Nature.

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Categories: Dumb Ideas

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