Apr 16 2024

Evolution and Copy-Paste Errors

Evolution deniers (I know there is a spectrum, but generally speaking) are terrible scientists and logicians. The obvious reason is because they are committing the primary mortal sin of pseudoscience – working backwards from a desired conclusion rather than following evidence and logic wherever it leads. They therefore clasp onto arguments that are fatally flawed because they feel they can use them to support their position. One could literally write a book using bad creationist arguments to demonstrate every type of poor reasoning and pseudoscience (I should know).

A classic example is an argument mainly promoted as part of so-called “intelligent design”, which is just evolution denial desperately seeking academic respectability (and failing). The argument goes that natural selection cannot increase information, only reduce it. It does not explain the origin of complex information. For example:

big obstacle for evolutionary belief is this: What mechanism could possibly have added all the extra information required to transform a one-celled creature progressively into pelicans, palm trees, and people? Natural selection alone can’t do it—selection involves getting rid of information. A group of creatures might become more adapted to the cold, for example, by the elimination of those which don’t carry the genetic information to make thick fur. But that doesn’t explain the origin of the information to make thick fur.

I am an educator, so I can forgive asking a naive question. Asking it in a public forum in order to defend a specific position is more dodgy, but if it were done in good faith, that could still propel public understanding forward. But evolution deniers continue to ask the same questions over and over, even after they have been definitively answered by countless experts. That demonstrates bad faith. They know the answer. They cannot respond to the answer. So they pretend it doesn’t exist, or when confronted directly, respond with the equivalent of, “Hey, look over there.”

The answer is right in the formulation of their position – “Natural selection alone can’t do it…”. I can quibble with the notion that natural selection only removes information, but even if we accept this premise, it doesn’t matter, because natural selection is not acting alone. Evolution is better understood as a two-step process, generating new information and then selecting the subset of that new information which provides an immediate survival advantage. There are multiple mechanisms for generating new information. These include mutations, where one amino acid is swapped out for another. But is also includes “copy paste” errors, in which entire genes, or sets of genes, or entire chromosomes, and sometime entire genomes are copied. It is difficult to argue that adding new genes to the total set of genes in a genome is not adding more information.

That is where evolution deniers play a logical game of three-card monte. They say – Ah, but mutations are random. They are “mistakes” that can only degrade the information. They are not directed or cumulative. This is the equivalent of arguing that a car cannot work because the engine cannot steer the car, and the steering column cannot propel the car. But of course, it’s the other way around. Similarly, mutations are not directed but they do add more information, and selection does not add more raw information but it can be directed and cumulative. The combination can add more specific information over time – new genes that make new proteins that have new functions.

The other major unstated assumption in this evolution denying argument is that there is some essential perfect state of a gene and any mutation is a degradation. But this is not correct. All genes are mutants, and there is no “correct” state or preferred state. There are only different states with different functionality. Functionality is also not objectively or essentially better or worse, just different. But some states may provide selective advantages under some conditions. Also, it is better to think of different functional states as having a different sets of tradeoffs. The statistically advantageous tradeoffs are more likely to survive and persist.

This is all logically sound, but what does the empirical evidence say? If intelligent design were true, then we would expect to see a pattern in biology that suggests top-down de-novo design. Genes would all be their own entities, made to purpose, without any remnants of a deep past history – at least, if you are willing to admit to a testable version of intelligent design. Proponents usually dodge any such tests by arguing, essentially, that – whatever we find, that’s what the designer intended.

In any case, if evolution were true we would expect to find a pattern in biology that suggests a nested branching relationship among all things, including genes. Genes did not come from nowhere, wholly perfect and complete. Genes must have evolved from ancestral genes, which further suggests that occasionally there are duplications of genes. That is how the total number of genes can potentially increase over evolutionary history.

Guess what we find when we look at the genomes of multicellular creatures. We find evidence of gene duplications and a branching pattern of relationships. A recent study adds to the mountain of evidence for this pattern. Researchers looked at the genomes of 20 bilaterian species – these include vertebrates and insects that have a basically bilaterally symmetrical body plan. What they found is that core genes and sets of genes that are involved with basic body anatomy are preserved across the bilaterian spectrum. Further, many of these core genes were the result of gene duplication, with multiple whole genome duplication events. They further found that when genes are duplicated, different cell lines can have different patterns of gene expression. This can even result in the evolution of new specialized cell types.

Gene expression refers to the fact that not all genes are expressed to the same degree in all cells. Liver cells express liver genes, while brain cells express brain genes (to put it simply). You can therefore have evolutionary change in a gene without mutating the amino acid sequence of the protein the gene codes for, but rather by altering the regulation of gene expression.

Gene duplication also allows for an important process in evolution – experimentation. When genes are duplicated, one copy can continue its original function. This, of course, is critical for genes that have core functions that are necessary for the organism to be alive. One copy continues this core function, while another copy (or more) is free to mutate and alter its function. This could lead to advantages in the core functionality, or to taking on entirely new functions. Any mutations that happen to provide even the slightest advantage will tend to be preserved, allowing for endless evolutionary tweaking and cumulative change that can ultimately lead to entirely new cell lines, tissues, anatomy, and functions. That certainly sounds like adding new information to me.

Not all changes, by the way, have to be immediately directed by natural selection. There is also random genetic drift. A redundant gene, unmoored from selective pressures, can endlessly “drift”, accumulating many genetic changes. If at any point, in any individual of any descendant line, that genes produces a protein that can be exploited for some immediate advantage, it will then gain a toe-hold on natural selection, and we’re off to the races.

When we look at the genomes of many different species, it’s pretty clear this is what has actually happened, many times, throughout evolutionary history. We can even map out a branching relationship of these events. Evolutionary lineages that are related have the same history of gene evolution (up to their last common ancestor). The quirky details of their genes line up in a way that can only be explained by a shared history. A shared function by a common designer doesn’t cut it. Many of these quirky details are not related to function, or there would be countless functional options. One would have to propose that the intelligent designer deliberately created life to look exactly as if it has evolved. That is yet another unfalsifiable notion that keeps intelligent design outside the boundaries of science.

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