What is a pseudogene, and why does it constitute such powerful evolutionary evidence for common descent over common design?
One of the big arguments between evolutionists and anti-evolutionists is over common design vs. common descent. We know, for example, that the wing of a bat, the arm of a human, and the fin of a dolphin all have the same basic structure (including dual forearm bones and finger bones).
Is this because all three species have a common ancestor or is this because they have a common Designer?
Those who do not believe in common descent argue that just as a Chevy and a Chrysler, or even a Chevy and a Harley, have many similar parts, they have obviously not descended from one another. They have similar parts due to having the same designer: man.
However, Dr. Edward Max argues that pseudogenes—broken genes that no longer work—indicate descent rather than design.
As an example, when cars switched from carburators to fuel injectors, car designers did not leave a broken carburator in the engine. The carburator was simply not put in the new design. Biological entities, however, do not have this option.
Dr. Max's page is one of the strongest arguments I have ever seen for evolution.
You probably know that Vitamin C is called a vitamin because our body needs it but can't produce it. If we don't eat vitamin C we will get scurvy and eventually die.
What you may not know is that this is not true of most mammals. Most mammals have an enzyme, called GULO, that produces vitamin C in their body. Only primates, such as chimps, gorillas, orangutans, and humans, require vitamin C, along with one rodent, the guinea pig.
Oddly enough, both primates (including humans) and the guinea pig have the gene to produce GULO, but it's a pseudogene in both—it doesn't work. If the similarities between other mammals and humans are due to common design rather than common descent, why would God bother to put the GULO gene in us at all? Why wouldn't he just leave it out rather than put a pseudogene in us?
Really, the same truth applies to the fin of a dolphin and the human arm. There are a lot of other bone designs that would work for a fin. In fact, all fish have a different fin design than dolphins. Only mammals—air breathers—such as whales and dolphins have fins designed like our arms.
If similarity in design was the point, why didn't God design dolphin fins like fish fins or shark fins rather than like a human arm? What sense does that make?
Dr. Daniel Criswell of ICR defends common design despite Dr. Max's arguments. He says that even if we really have a GULO pseudogene, it could have happened since Adam. [It's a common theory of young earthers that we have been "devolving" since Adam.]
It's interesting, though, isn't it, that it only happened to us, chimpanzees, and other primates?
I need to address here the fact that it also happened to guinea pigs. The GULO gene is damaged much differently in guinea pigs than in primates (and ourselves). There's a much different code sequence.
The primate pseudogenes, on the other hand, are very similar. Dr. Max writes:
If a primate is no longer making GULO, we might expect mutations to accrue at a somewhat steady rate. Thus, not only should primates have a similar pattern of mutations, but the primates that we believe are more closely related (such as chimps and humans) should have more mutations in common with each other than they do with other primates. This is the pattern we see.
In response to those who argue that the GULO gene became a pseudogene independently in all these species, just by chance, he writes:
It is extremely unlikely that we would see a pattern of mutations that forms what looks like a family tree simply by chance.
It always amazes me that the very people who say that evolution couldn't have happened by chance go on to appeal to wildly unlikely chances wherever they wish. Natural Selection, by the way, is "selection," not chance.