No. 100: Jul-Aug 1995
Neo-Darwinists are chained to the premise that evolution proceeds "blindly"; that is, mutations are random and unrelated to the biological needs for survival. This assumption is enshrined in R. Dawkins' book The Blind Watchmaker. Catchy though this title is, it looks more and more like the Watchmaker sees something.
For over a decade, experiments have hinted that those mutations that are helpful to an organism's survival occur more often than those that are not "adaptively useful." This controversial phenomenon is termed "adaptive mutation." (SF#64 and SF#96*) A recent issue of Science presents two more papers that seem to confer the gift of sight on the old Watchmaker.
Biochemist J.A. Shapiro, in a commentary accompanying the two Science papers, highlights a significant feature of adaptive mutation in bacteria: The genetic changes involved are multicellular. In other words, DNA rearrangements in one cell are actually transferred to other cells. But most profound of all for the whole science of biology is his sentence:
"The discovery that cells use biochemical systems to change their DNA in response to physiological inputs moves mutation beyond the realm of 'blind' stochastic events and provides a mechanistic basis for understanding how biological requirements can feed back onto genome structure."
(Shapiro, James A.; "Adaptive Mutation: Who's Really in the Garden?" Science, 268:373, 1995.)
Comment. Random mutation has been a linchpin of Neo-Darwinism because it is "scientific"; that is, non-supernatural. We see in adaptive mutation that other scientific mechanisms may indeed exist that make biological evolution more than just a plaything of chance. Furthermore, since some species (You know who you are!) can modify environmental forces, these species can, in principle, control their own evolution -- for good or bad -- and may in fact be doing just that.
*SF#xx = Science Frontiers #xx.
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