Fish Gene Gives Darwinists Hope
It doesn’t take much to excite an evolutionary biologist. A little bit of microevolution that might be a stepping stone to macroevolution is all it takes. This story almost reads like a Good News – Bad News joke. The good news is that one gene that regulates the spines on one kind of fish has been found, that might provide a clue how a noticeable change between populations could evolve. The bad news is expressed in an opening statement by Neil Shubin and Randall Dahn in their summary of a scientific paper published in the April 15 issue of Nature1:
Darwin’s lament that “Our ignorance of the laws of variation is profound” has described one of the persistent problems in evolutionary biology for the past 145 years. How does genetic variation – the raw material of evolution – arise within populations, and how does it evolve to make species anatomically and behaviourally distinct?
To attempt an answer to these profound questions, Shubin and Dahn refer to a paper by Shapiro et al.2 in the same issue. Shapiro’s team found a gene in threespine sticklebacks that controls the size of their “stickles” or bony spines that grow out of the pelvic girdle on these fish. These spines are apparently defensive structures in the sea-going species, but are reduced in size in their freshwater cousins. Experiments with the gene show that it can reduce the size of these limbs. That leads to a counter-intuitive principle, according to Shubin and Dahn: “Surprisingly, some of the most significant novelties in the history of life are associated not with the evolution of new structures but with the loss or reduction of primitive ones.” As examples, they point to snakes and whales, who supposedly lost their legs. Some animals can jump, fly, or run better without their limbs, they claim. Similarly, freshwater stickleback fish might do better without their spines, either because there is insufficient calcium in the water to grow them, or predatory invertebrates might find them to be convenient handles.
The gene the paper identified, Pitx1, is vital; in fact, “Pitx1 mutations in mice are often lethal, because they cause developmental abnormalities of the head, face and some glands.” This leads to another counter-intuitive principle: “How, then, could alterations in this gene be involved in limb reduction in living populations of stickleback fish? The answer is that the regulation of Pitx1 – not the protein encoded by the gene – has changed.” Specifically,
Shapiro et al. found that the sequence of the protein-coding region of the Pitx1 gene is identical between the different populations of sticklebacks. But the gene’s expression pattern is altered markedly: the population with complete pelvic loss shows no Pitx1 expression in appendages but retains patterns of gene activity in other areas, such as the thymus, olfactory pits and caudal fins (Fig.2). This type of localized decrease in the activity of Pitx1 can result in pelvic-fin reduction without affecting other parts of the body.”
Thus, a small microevolutionary change might lead to macroevolutionary effects: “Regulatory changes affect when and where a gene is active, not the actual product of the gene. So these types of changes are often involved in non-lethal and rapid morphological change, and are likely to be extraordinarily important components of evolutionary history.” They do not explain what kind of mutation changed the expression of this gene. Instead, Shubin and Dahn argue that stratigraphic evidence suggests this change took place in only 10,000 generations. They reason that “Extrapolating these results to other taxonomic groups leads to the conclusion that major morphological change can evolve rapidly through regulatory changes in a small number of genes.” Furthermore, Shapiro’s paper might demonstrate how parallel evolution could occur, and why “some evolutionary changes occur more readily than others.” Shubin and Dahn feel this finding might even lead to a general principle of macroevolutionary change.
Their ending paragraph, however, casts only the faintest glimmer of hope on this 145-year-old problem:
One of the central mysteries of evolutionary biology has been the relationship between microevolution and macroevolution. How can an understanding of the evolutionary mechanisms that act in populations today explain the types of variation that distinguish higher taxonomic groups, such as genera, families or even phyla? Can an understanding of population-level processes explain major evolutionary events such as the Cambrian explosion – the period around 550 million years ago when complex animal life took off? Perhaps so. Shapiro et al. might have discovered a smoking gun – a real example of a type of macroevolutionary change that is produced by genetic differences between populations.
Other science news outlets quickly picked up on this story. The BBC News announced that “Scientists have discovered a genetic basis underlying the evolution of fewer limbs in animals,” and claimed that “Limb loss is implicated in a number of big steps in evolution.” Science Now reported that “researchers have found that a simple change of gene activity could make all the difference–a rare demonstration of how a small genetic change can make a relatively rapid impact on an organism.”
1Neil H. Shubin and Randall D. Dahn, “Evolutionary biology: Lost and found,” Nature 428, 703 – 704 (15 April 2004); doi:10.1038/428703a.
2Shapiro et al., “Genetic and developmental basis of evolutionary pelvic reduction in threespine sticklebacks,” Nature 428, 717 – 723 (15 April 2004); doi:10.1038/nature02415.
We need a new category for stories like this. Is there a word for gaining an inch and conceding a mile, gaining one small hill but losing the war, spending one’s life savings on a slot machine and winning a dime? That’s the spirit of this story; it’s a Pyrrhic victory. Shubin and Dahn talk like they will soon be proud winners of millions of dollars from Nigeria, if they can just round up a little more money.
Notice the big picture. Here we are, 145 years after Darwin started a revolution in biology that took over the intellectual world, and they admit right up front that Darwin’s own lament, “Our ignorance of the laws of variation is profound,” is still a “persistent problem” today. Even after we have sequenced the genomes of dozens of organisms and scoured the world for fossils, and garnered data beyond Charlie’s wildest dreams, evolutionary biologists are still singing the same blues. Then, after all their hype about what this stickleback tale might mean, they admit that “One of the central mysteries of evolutionary biology has been the relationship between microevolution and macroevolution.” Do you understand what they are telling us?
Since Charlie wrote his “abominable volume” in 1859, we have been told that macroevolution is a scientific fact, yet were provided only microevolutionary observations and macroevolutionary tales, with no scientific connection between them. Evolutionists only assume the two are connected somehow. What if there is no connection? What if variation has limits, and the higher taxonomic groups have always been distinct and separate? He mentions the Cambrian explosion (see next headline), which would lead an unbiased observer to conclude that all the major animal body plans appeared abruptly on the earth without ancestors. Small variations within groups have undoubtedly occurred since then, but Shubin and Dahn’s incriminating admissions indicate that Darwinians have failed to demonstrate macroevolutionary change, and thus failed to demonstrate common ancestry of all living things.
Notice how tiny their evidence is. They’re only talking about stickleback fish, for crying out loud, and for crying even louder, they’re talking about a loss of genetic information, and for screaming hysterically, they are talking about one gene that is identical between two populations, that if mutated, causes death! How on earth can an evolutionist find any hope in that? Picture a little boy at a waterfall, who has been convinced by a trickster that water flows upward. At the base of any waterfall there are droplets that bounce and splash up temporarily. The boy becomes fixated on those splashes, hoping against hope that his observations will, in time, demonstrate the truth of the theory he has been led to believe. All the while, the big picture demonstrates the exact opposite.
Stories like this lead some non-evolutionists to ponder a future day when the culture will look back at 2004, incredulous that intelligent people could believe such things, and will laugh at the flimsy arguments used to support them. Like Søren Lovtrup wrote in Darwinism: Refutation of a Myth: “Micromutations do occur, but the theory that these alone can account for evolutionary change is either falsified, or else it is an unfalsifiable, hence metaphysical theory. I suppose that nobody will deny that it is a great misfortune if an entire branch of science becomes addicted to a false theory. But this is what has happened in biology: … I believe that one day the Darwinian myth will be ranked the greatest deceit in the history of science. When this happens many people will pose the question: How did this ever happen?” (Source: IDEA Club. Browse their large collection of quotations on Darwinism.)