Ok, yes it is… sort of.
There is a tired but persistent argument that DNA is a code, and codes are designed things. The very fact of it being a code proves that there must have been someone who designed the code.
This argument distills to improper word use. A code, by the strictest definition, is in fact something designed by intelligent beings. It is a system of symbols that either arbitrarily or by some system represent various things. The alphabet I’m using to write this article is a code. There’s nothing about the individual letters that have any inherent meaning. They don’t do anything in and of themselves. By agreement between multiple humans, we have a legend, or a key, which most of us learned in grammar school. By using this legend, we can look at anything in the code “English” and through substitution, come to the knowledge of the concepts symbolized by the various letters.
This is the traditional idea of a code, and it is what theists think they mean when they argue that DNA is a code. The thing is, DNA is not that kind of a code. DNA is a polymer, composed of individual chemical units called nucleotides. There are four types of these nucleotides, and we humans have decided to call them adenine, guanine, cytosine, and thymine. These names are not entirely arbitrary, but in the end, there’s nothing magical about them. We could call them Blob, Clob, Dob, and Emu, and they’d still be the same.
The nucleotides in DNA are often said to be the “blueprint” or “code” which define a sequence of messenger RNA which in turn defines at least one protein. In a sense, these proteins are the building blocks of life, and DNA is the “code” which determines the qualities of the life that will be built.
The problem with the theist argument, however, is that the DNA code is not arbitrary, and it does not rely at all on the agreement of sentient beings. In fact, it is exactly the same as any other dynamic chemical process. When you see an explosion on TV, you’re watching a chemical reaction that was controlled by the same kind of “code.” Crystals grow based on such a code. Stars give off light and energy from the same kind of code.
All DNA is, to the chagrin of creationists, is a very, very complicated organic molecule that can react in a staggeringly large number of ways with other organic molecules. Unlike an explosion or a crystal, which can be described mathematically with a few simple formulas, the process of building a living thing is several orders of magnitude more complicated. It takes perhaps 10 billion bits to convey all the necessary information needed to build a human, and the process is never really finished until the human dies, so we’re talking about a very, very long process by comparison with an explosion, and billions more unique steps than the formation of a crystal.
Yet, it’s the same process. This molecule, when in the presence of that molecule, will bond and make this new molecule. It’s just chemistry.
The thing is, we humans recognize the complexity of the chemical process we call life, and we notice that it is not completely dissimilar from the process by which we build a skyscraper or a watch. We have a set of instructions, and we refer back to them throughout the process of putting materials together in very specific ways, until we have a finished product. We like to argue that messenger RNA is “referring to the instructions” to figure out which protein to build in the same way, but it’s not. Neither DNA nor RNA is sentient. They are both just doing what chemicals do. DNA is more akin to a catalyst than a set of instructions. That is, DNA stays essentially the same throughout the building process, but it is facilitating chemical reactions the whole time it is part of a living thing.
So, here is the ultimate problem with this theist argument. DNA is not an arbitrary set of symbols that “stand for” something else that will be interpreted through some kind of a legend. It is a set of chemicals which are nonthinking, and have no choice but to do what they do, in the same way that a crystal has no choice but to grow when in the presence of the appropriate aqueous solution. DNA is just a very, very, very complicated molecule that happens to be capable of facilitating incredibly complex sets of chemical reactions. No amount of wishing or wanting on the part of intelligent beings can change the laws of the universe which dictate the way DNA works. (We could, through our agreement, change the way “sh” is pronounced, or alter the spelling of a word: “color” vs. “colour,” for example.)
Sure, it seems magical that something as simple as four little nucleotides could be responsible for all the diverse life on the planet, but our sense of wonder at the versatility of carbon shouldn’t woo us into the false belief that incredible versatility is equivalent to design. DNA is not a “code” in the normal sense of the word. We call it a code because it gives us an easy way to think of the process by which a strand of DNA is responsible for the building of a living thing. (Consider that we call both a string of computer code and a bundle of RNA a “virus,” but they are very different things that behave similarly.)
That’s it. When we look at a particular sequence of nucleotides, we can recognize that the chemical reaction they facilitate will produce a certain protein. This is no different from looking at a few grams of sodium or potassium and recognizing that in the presence of water, they will react in very specific ways to produce a violent exothermic reaction. If DNA is a code, then so is every other molecule in the universe. It’s just the consistency of the laws of nature. This, in the presence of that, will do the other.
So no, DNA is not a code. It is analogous to a code in enough ways that it makes sense for us to refer to things like the “genetic code,” but in the end, we’re just not talking about the kind of code that would make the theist argument valid.