Pseudogenes and Natural Selection

It turns out that the DNA of all organisms is filled with things called pseudogenes. A pseudogene is defined like this[1]:

“A sequence of DNA that is very similar to a normal gene but that has been altered slightly so it is not expressed. Such genes were probably once functional but over time acquired one or more mutations that rendered them incapable of producing a protein product.”

Basically it is a gene that doesn’t do anything. That’s because it is not needed any more. Blind cave fish, for example, have pseudogenes for sight. The genes used to be needed for them to see, but once the fish began to live in total darkness, the gene wasn’t needed any more. So the gene developed mutations that “broke” it.

These genes exist. The question is whether or not natural selection should eliminate these genes.

Here’s how one creationist asked about them:

> Actually the "theory" of Fisher, Wright, Mayr and
> even Dawkins predicted with descend from the creature
> with the 'superior' genes.

> Not from the viruses and a creature with all these
> failed genes.

The question, then, is whether or not a DNA that lacked “pseudogenes” would be superior to one that included “pseudogenes”.

There really isn’t reason to think that is the case. Pseudogenes add extra base-pairs to the genome, but there isn’t any empirical evidence that indicates that is a bad thing. Other than those extra base-pairs, they have no effect at all. There is even something called “polyploidy” where entire genomes are duplicated while copying. This happens primarily in plants. It results in a doubling of the genome size. There seem to be no ill effects for the organism when this takes place.

In fact, an argument could be made that such pseudogenes are really required for evolution to take place effectively and efficiently. That’s because without the genetic material provided by such pseudogenes, the percentage of mutations that are beneficial would diminish considerably.

If there were no pseudogenes whatsoever, then every gene – by definition - would be one that is required for the organism to survive. In that case, even if a mutation occurred that was beneficial it would result in the loss of another characteristic that was also beneficial. That would mean that some percentage of potentially beneficial mutations would be rejected simply because they are not as beneficial as the gene that is being replaced.

As an analogy consider adding a new room to a house.

In the first case, let’s assume that every single room is used. There is no unused space. Now let’s say that we want to add a new bathroom. In this house, in order to do that, we would have to lose one of those other rooms that is being used – possibly we’d have to give up a bedroom. It might be the case that the bathroom has more utility than the bedroom. But it might also well be the case that the bedroom is actually more useful than the new bathroom. It certainly makes the decision about making the conversion more problematic.

But consider the case if the house has extra rooms that are not used. In that case the decision is much easier. You have everything to gain and nothing to lose.

Such is the case with pseudogenes in DNA. They provide extra “unused space” that makes it easier for mutations that are beneficial to become part of the DNA.

If God “designed” DNA, He did so in a way that makes evolution perform more efficiently.

It appears that God is an evolutionist!

[1] Definition from: “Talking Glossary of Genetic Terms” compiled by the National Human Genome Research Institute, referenced on April 6, 2009