Very often you will her creationists talking about the blueprint of DNA or DNA as a computer program or all the analogies… that just don’t work. Analogies are great for teaching very basic principles of a concept to people who don’t have the background to handle the full details of a concept. For example, high school students in their first ever biology course.
But these analogies are not the thing being discussed. There are no scientists who talk about the DNA blueprint, in their scientific papers (that I’m aware of). This is because they are experts who understand the details and they are communicating with other experts who understand the details.
Trying to make an argument against evolution (or genetics or GMOs) and using analogies as the base of the argument is a fundamental mistake. No argument that uses analogies is a legitimate argument against something. This is simply because analogies are not perfect representations of the thing.
An analogy is a simplified version of a thing that is compared to something that a person should already be familiar with. To a person born in an urban environment you might have to describe a horse as like a big dog that people ride on. That’s an analogy. But you can’t use the fact that all dogs are too little to ride on as an argument against the existence of horses. That sounds like a silly example, but it’s exactly the same argument that creationists are using against evolution. Because a complex watch can’t self assemble itself and evolve, then complex organism can’t self assemble and evolve. That is the creationist argument.
The first example of an failed analogy is that the DNA is the blueprint of the body. While it’s true that the DNA contains all the coding needed to develop all the proteins and DNA control systems for the body, there are some major differences between DNA and a blueprint.
You can look at a blueprint and there is a reasonable expectation that you can discern the final product from the blueprint. This is not possible with DNA. Not only can we not determine what proteins actually do by just looking at them. We can’t judge how the environment will impact the adult organism. Plus you can compare the finished product to the blueprint to ensure that everything is just so. That doesn’t work in organisms. Mutations, transcription errors, translation errors, viruses, etc. can all change the finished product slightly and result in the DNA actually not matching the organism.
With a blueprint, we can see exactly what parts go together in what pattern, using various materials to result in a finished product. An organism takes in materials throughout it’s life and occasionally changes based on those materials. A lack of calcium, for example, can result in damaged bones and loss of teeth. But the organism can still function. Unlike a house with a lack of nails.
Another analogy that is often used is that DNA is like a computer program. Computer programs are complex and written by a programmer, therefore organisms’ DNA is also written by a designer. DNA is nothing like a computer program. A computer program executes steps in a particular order. DNA can be transcribed in any order and each cell on uses part of the DNA. Again, a reasonably competent programmer can understand the code, figure out what it’s doing and even repair the program. Not so with DNA.
DNA is also not something that runs on some kind of platform. It is an integral part of the ‘platform’. Indeed, it is the “hardware” as well as the “software”. Oh and it’s also the memory and it’s also the CPU. Even further, the DNA can undergo some pretty drastic changes to the code and still work. In fact, random changes to DNA can actually result in new effects and improvements in the resulting proteins. Which simply does not happen with software.
I will note that there are software packages called genetic algorithms. These are software platforms that run genetic code. As such, the programs themselves do not change as DNA would, but the data that the program works with changes as DNA would.
Then we hear about how organisms are like watches. Complex watches require a designer, therefore, so do organisms. Of course watches don’t self assemble themselves from the instructions contained in one (and each and every) part of the watch. Watches don’t sexually reproduce. Watches are made in human built factories. Using human designs. Watches invariably don’t work when there are unintended changes to their structure.
All this is unlike organisms which do self reproduce, sometimes using sex which shuffles up the DNA of two other organisms. The resulting organism usually works just fine. Sure sometimes there are major mistakes in the shuffling process, but still many, many organisms are produced using this method.
DNA is an amazing chemical compound. Parts of it store the code for proteins, some of which influence how the DNA code is read and translated into more proteins. There is an error correction system which (while not perfect) prevents massive genetic mistakes from appearing during the normal process of growth.
Using cells that have not differentiated into a specific type of cell in a body (a nerve cell or a muscle cell for example), so called stem cells, theoretically a complete new organism could be grown. Try that with a spark plug or a watch hand. This has been done with sheep and cats. But these clones can and do look different from the parent. This is due to environmental factors and how they can change or influence the expression of DNA into proteins or even whether certain parts of DNA begin the process for producing proteins or not.
Changes can occur in the DNA that have no effect on the organism at all. Or that change can have a large effect. Sometimes the change is negative, sometimes positive, but mostly it’s not a change at all.
Finally, I’d like to point out something else. DNA (any biological system) are not really ‘machines’. They are extremely complex chemical compounds. The actions that they can perform (muscles for example) are not purely mechanical like a human built machine. They are purely chemical, resulting in a change in shape of a chemical compound. This allows a different point of the compound to attach to another compound. When it reverts back to its original shape, it remains attached at that point and thus moves forward and the sequence continues. While the bones and muscles in our bodies have the macro effect of a simple machine (levers), the micro effect is not mechanical, but chemical. There is no system yet built by humans that work using the same principles as muscles. I think we’re getting close, but they much simpler.
The take away from all of this is that analogies are teaching tools. But if someone is making an argument using an analogy, then they are wasting their breath. If we want to argue about an aspect of DNA, then we talk about that aspect of DNA… not how DNA is like a hard drive and therefore calling it software is wrong.
The experts are busy arguing about the role of methylation in gene expression and creationists are arguing that DNA is really complex and therefore must be designed. We know it’s really complex and if you want to argue about particular points, then the best place to start is by performing experiments that support creationist notions in the lab. Here’s one, at what point does evolution become impossible? What factor is it that allows “microevolution”, but prevents “macroevolution”. In your experiments, explain the difference between the two (hint: there isn’t a difference).
If you see someone arguing using an analogy, then you are free to ignore them. They don’t know what they are talking about. And the details of a genetics course would blow their minds right out of the water. There are some creationists who have taken such courses, but they choose to ignore what they learned to promote a religious agenda. That’s not science’s problem. It’s their problem.