Creationist Argument — “Mutations cannot increase information”
Before reading this article, please read ‘An Introduction to Christian Creationism’, which should inform you on the nature of creationism as I refer to it here. It will make understanding this a lot easier. Be warned that a basic understanding of genetics would also be helpful.
Over the next few months/years, I’m going to be writing articles on the specific arguments that creationists use to try and undermine the validity of the theory of evolution. Today, I’m going to be talking about a classic argument used by basically every creationist out there: the argument that evolutionary changes cannot be brought about by genetic mutations.
The argument goes as follows:
Genetic mutations cannot cause an increase in the information content in the genome, and therefore cannot produce evolutionary changes like the theory of evolution predicts.
The above statement is the basic form of the argument that you will see everywhere, from Answers in Genesis to the Discovery Institute. Creationists consider it to be one of their strongest arguments against evolution (and therefore, in their eyes, for creationism).
Let’s examine this argument in detail. Firstly, what are the premises of the argument? Well, it could be reasonably said that they are that evolutionary change requires informational increases in the genomes of organisms, that mutations are the only ways that this can happen (if other processes accounted for an increase, it would not be an argument against evolution), and, of course, that mutations themselves cannot produce informational increase. The first premise is not strictly true: evolution is defined as the adaptation of a population of organisms to its natural environment, and this does not necessarily require the information of the genome to increase. It can as easily decrease.
Let me explain with an example.
Say you have a population of organisms that have long tails. The genetic coding for tail length lies within a certain region in the genome of the organism, and the number of genes in that region that any organism has is directly proportional to the length of its tail. One day, a predator is introduced to the habitat of these organisms, and due to their long tails, it finds it easy to catch and eat them. In such a situation, having a tail that is shorter than the rest of the population would be an advantage, no? So, due to random mutations in the next generation of organisms, some members of the population now have shorter tails than the rest. This means that they get eaten less often, and therefore have more offspring with short tails. After a while, the entire population has short tails.
Evolution, or adaptation to the environment, has unquestionably occurred. But what has happened to the genomes of the organisms? Recall that the number of genes in a particular area controls the length of the tail. So, for the tail to get shorter, one or more of the genes in the “tail length” region must have disappeared! Is that not a decrease in the information of the genome? I would say so.
How about the other premises? Creationists are most certainly defining a “mutation” as a point mutation, which, if you don’t know, is a single nucleotide base pair substitution (for example, going from adenine to guanine). Other mutations do exist, such as chromosomal inversions, where parts of chromosomes are inverted around a certain point, causing genes to be rearranged, and gene duplication, where a certain gene is copied incorrectly during cell division and one cell ends up with two copies and the other no copies, but I’ll talk about these later.
So, do point mutations cause informational increases in the genomes of organisms, like creationists say they don’t? Well, no, they don’t.
Yes, it’s true, the creationists are correct about something. However, like most of their arguments, this one revolves around a central speck of truth with horrifically false extrapolations grafted onto the side caused by a lack of further knowledge. Point mutations don’t cause an increase in the individual genome’s informational content, but rather in the population’s gene pool as a whole. Think about it: changing one base pair in a genome doesn’t change the informational content at all, you’ve just removed one allele (gene variation) and replaced it with another. But when you talk about the gene pool, where multiple alleles can exist side by side, a point mutation becomes the bringer of new genetic variation, which then can be pruned back with natural selection into a different population of organisms.
Right now, the creationist reading this article (yes, you!), is thinking/yelling: “But that doesn’t allow for the types of changes that evolution predicts! What about molecules to man? It’ll require a little bit more than shuffling the alleles of a couple of genes to turn a bacteria into a cat!”
Well yes, my probably American friend, but I’m not finished yet. Remember gene duplications? Yes, those things. Well, they play a big role in the increase of information in the gene pool and the genomes of individual organisms.
As previously mentioned, gene duplications occur when one gene is copied incorrectly and the organism gets two copies of the same gene in its genome. How does this relate to information increase? I mean, you’ve only got a copy of something you already had! But remember point mutations, and how they changed one gene into an allele of itself. What if you had a point mutation in one of the copies, and the other remained the same? You would end up with the original gene and a variant of that gene, in the same organism. This means there can be a completely new gene, given enough mutation, and evolution can progress on its merry way, adding different body morphologies, biochemical pathways and transcription factors. Going back to our tailed organisms, such a gene duplication could allow for the recently short-tailed organisms to change back into long-tailed variants if the environment required it. And by logical extension, if a loss of a tail length gene was a decrease in information, then gaining a gene is an increase in information.
So, I hope you now see how this argument falls down. If you have any questions, please post a comment below and get the dialogue rolling. I’ll happy to answer any queries.