A mutant shrimp is being claimed as “a landmark in evolutionary biology” that proves Darwin’s critics wrong. But its nothing of the sort, says biologist Jonathan Wells.
A research team headed by William McGinnis at the University of California at San Diego has reported discovering a DNA mutation that produces shrimp without hind legs. Their report is being published in the February 6 issue of Nature.
Since shrimp normally have lots of legs, and insects have only six, the U. C. San Diego researchers claim they have discovered the genetic mechanism that enabled terrestrial insects to evolve from aquatic ancestors hundreds of millions of years ago. The researchers also claim that this discovery undercuts a primary argument against the theory of evolution, because it shows that major mutations do not result in dead animals.
Not so, says Dr. Jonathan Wells, who has a Ph.D. in molecular biology from the University of California at Berkeley and is currently a senior fellow at Discovery Institute in Seattle, WA. Wells calls the U. C. San Diego claim “greatly exaggerated,” and describes the mutant shrimp as “an evolutionary dead end that tells us little or nothing about how insects originated.”
Wells points out that the mutation reported by McGinnis and his colleagues occurs midway through development, after the embryo is already a shrimp. “The mutation does not transform the embryo into anything like an insect, but only into a deformed shrimp thats missing its hind legs. Whatever produced the first insect would have had to transform the entire embryo from the very beginning.”
Wells adds that critics of Darwinism do not claim that major mutations result in dead animals, but only in animals that are less fit. Evolution depends on increases in fitness, since animals that are less fit tend to be eliminated by natural selection. Major developmental mutations, however, always decrease fitness.
Wells says he is not surprised that the researchers are making so much of their discovery. “There is no evidence that genetic mutations can produce the major changes required by evolution, so people who believe strongly in the theory often exaggerate the evidence to make it look better than it really is.”