How Blind Cave Fish Lose Color
A study on cave fish revealed that several populations can have mutations to the same gene. A gene that produces melanin, named Oca2, was found to be mutated in two separate populations of cave fish, resulting in albinism. This same gene can produce albinism in humans.
The replicated experiment is a powerful tool for experimental science, but typically unavailable in the study of evolution. Cave adaptations have evolved in many species independently, however, and each cave species can be considered a replicate of the same evolutionary experiment that asks how species change in perpetual darkness. A frequent outcome is that the species lose pigmentation or become albino. Cavefish, therefore, are a rich source for the examination of the evolutionary process. (Emphasis added.)
It was surprising to the multidisciplinary team why this gene, and not others that can also produce albinism, was implicated. “One possibility, suggested by the researchers, is that it is a large gene presenting a big target for mutations, and it seems to have no other functions besides helping to make melanin,” the press release on EurekAlert states. “Therefore, it doesn’t diminish other aspects of fitness when it is mutated.”
Here is a situation where “evolutionary theory” is compatible with intelligent design or creationism. It’s not a case of evolution in the sense of new functional information being added; it’s a case of function being lost. How this loss of information affects an organism is interesting, and it is worthwhile question to ask why two cave fish populations would get the same mutation to the same gene. If one assumes that the fish began with fully-operational Oca2 genes (as in creation/design), then it follows that a reproducing population of fish with mutations in that gene will lead to a population of albinos, if the benefit of having color no longer matters in the cave environment. This is downward evolution, not upward evolution. The story differs from the just-so storytelling of Darwinian theory, because we have plenty of empirical evidence that mutations lead to loss of function, but no evidence that mutations can produce new function. Darwinists try to call this “evolution” (in the sense of change over time), but it doesn’t do anything to help Charlie’s story that fish evolved from pre-fish, or ultimately, from one-celled organisms. Creationists could just as well study loss mutations to investigate the extent of genetic load (deterioration) over time since the original perfect creation; convergent devolution, therefore, is non-controversial, but convergent evolution is what lacks empirical support.