Is Junk DNA Evidence for Darwinian Evolution?

Post Author: Bill Pratt

One of the most common arguments you will hear that Darwinian evolution must be true is the “Junk DNA” argument.  It goes like this:

There are significant stretches of the human genome that appear not to code for any biological function.  This is what you would expect if millions of years of random genetic mutations occurred in the genome.  This junk DNA is simply left over from evolutionary history and is serving no purpose any more.

The argument makes sense, but there is only one small problem.  Every year that goes by scientists are discovering more and more functions for this junk DNA.  It turns out that it’s not junk after all.  If the junk DNA is coding for biological function, then this particular evidence for Darwinian evolution falls by the wayside.  Not only that, but this becomes positive evidence for the Intelligent Design community, as they have been predicting this very finding.

Take a look at this video where ID scientists discuss Francis Collins’ use of the “Junk DNA” argument in his book The Language of God.

12 thoughts on “Is Junk DNA Evidence for Darwinian Evolution?”

  1. Bill, I appreciated what you are saying: if an argument rests on the existence of DNA that makes no sense to us, then one of the necessary underlying assumptions is that we understand everything that is meaningful. In any field, an argument based on the perfect completeness of my understanding is hazardous at best.

    My question may be a little far afield for this thread; but I have a hard time with the distinction between “Darwinian evolution” and ID in the first place.

    Now, I am not familiar with the ID literature, I just haven’t had the interest in it (Although my son-in-law, who completes his PhD in Biochemistry this month, is), but it seems that the difference lies in speculations about the underlying cause of the mechanism, rather than the mechanism itself. Yes, ID attempts to bring probability to bear on that question, but that is still outside the issue of evolution.

    My picture of the question is as follows, and I’m asking not as a partisan, but to see if I have framed the difference correctly:
    Assume evolution as a roulette wheel you spin the wheel, and take your chance on a mutation. Being helpful. Both camps agree so far. The difference is that the ID folks (and if so, I’m with them) think that the game is rigged; that even though it may look random, the house gets the results it wants.
    Is that the picture? Or am I missing something?

  2. Eric,
    Thanks for the question and let me see if I can clear things up a little. ID, as applied to biology, points out that there exists in certain biological structures (DNA being a good example and the subject of an entire book by ID author Stephen Meyer) complex and specified information (CSI) content. They argue that the only known mechanism for the creation of CSI is intelligent agency. Therefore, intelligent agency must play some role in the causation of biological structures which contain CSI. As a corollary, the Darwinian mechanism of random genetic mutations and natural selection are not sufficient to explain the causation of biological structures containing CSI. The Darwinian mechanisms are non-intelligent.

    So, ID’s attack is limited to the mechanisms which cause evolution (evolution being the development of biological life from the less complex to more complex over the last 3.5 billion years), not evolution itself. Within the ID community, some accept that all living things are linked through common ancestry and some do not accept that fact. ID, per se, does not have a dog in that hunt. ID is purely interested in the mechanisms that have caused evolution to occur.

    Does that help?

  3. Bill Pratt,

    Are you saying that mutation and adaptation do cause evolution, but are not sufficient to get us where we are today, and ID claims there must be an additional third factor—intelligent agency—involved as well? (If my question is not clear, I will be happy to re-phrase it.)

  4. It sounds like the sole difference is that the process of mutation is not purely random, but that thiere is an intelligence behind it, using this mutation towards a purpose sometimes beyond immediate adaptation.

    Dagwood, as you can probably tell, I’m not trying to answere your question, but doing the same thing myself – trying to clearly define terms.

  5. Dagoods,
    Yes, the idea is that mutation and natural selection play a role in evolution, but that they are not sufficient to explain much of what exists in biological life. Some kind of intelligent agency must also be involved. The first point (that random mutation and natural selection are not sufficient) is actually supported by many evolutionary scientists, but the second point (intelligent agency) is not.

  6. Thank you, Bill Pratt.

    Please understand I am not well informed regarding evolution, so my questions may appear simplistic to someone better equipped. I am trying to understand the claims being made.

    If I understand it correctly, Intelligent Design says there are two types of evolution that occur:

    1) Mutation + Adaptation.
    2) Mutation + Adaptation + Intelligent Designer.

    If I have that correctly, my obvious question is this: How do we determine the difference between (1) and (2)?

  7. Dagoods,
    Determining the difference between 1 and 2 is what much of ID literature talks about. The simple explanation is that the detection of complex specified information in a biological structure signifies intelligent causation. I would recommend reading Signature in the Cell for the most recent treatment, although this book builds on many others. It’s a good place to start.

  8. Again, thank you, Bill Pratt.

    Here, let me explain my problem. The highest I ever went in math was Calculus I in College (and I barely made it through that!). I took Biology I in college, but this was at a conservative Christian college in the 1980’s, so you can imagine how much evolution was discussed. Or Intelligent Design.

    What I know about life development you can write on your thumb. I’ve read books (and numerous articles) from scientific standpoints, YEC, OEC, theistic evolution and Intelligent Design. Perhaps by sheer bad luck, my introduction to ID was Philip Johnson’s Reason in the Balance. (On the recommendation of a Pastor right after I deconverted. His words were, “As a lawyer, you might be interested in how a lawyer approaches theism from a different perspective.”)

    This was a mistake—I may not know science, but I know bad lawyerly arguments. And Mr. Johnson’s book was full of ‘em. I started checking quotes, and saw them being used out of context; I saw the logical issues and rhetorical pleas. Not the best way to convince me regarding ID.

    I can read positions from both sides, yet to be completely honest with myself, I do not have enough background to confirm whether one side or the other is being forthright.

    For example, as you know I have studied historical Christianity within the first 2 centuries. So if some apologist coughs out, “James was killed by a club” I know immediately what their source was, what their source’s source was and what their source’s source’s source was. I know the issues, I know what I am looking for, I know the implications.

    When you mention CSI, I looked up the first two links from a google search: 1)Wikipedia on CSI and dissecting CSI. I can read the articles. I can follow the English sentences, but what I cannot do is determine which side is convincing. Is the math correct? My son’s 7th grade math makes me re-review; what chance do I have on information theory?

    So Dembski says one thing, someone else says another, and I cannot divorce myself from my own personal bias, as I don’t have enough background knowledge to fully understand what either is saying. (And to be fair, I keep thinking of Philip Johnson in combination with Dover and throwing up a little bit in my mouth.)

    The reason I was asking is not for some “gotcha” moment; I am asking because you are (with no disrespect intended) a regular guy. You believe this stuff—you find it persuasive. I know the books I am supposed to read, including the current flavor—Signature in the Cell. I am also aware I can find reviews by scientists who roundly pan it. Its not what each side will say—it is who is being more accurate.

    Maybe I am saying I don’t want a book recommendation until I understand why I should read such a book. Especially realizing I don’t know enough to even know what I should be double-checking on Meyer and what I don’t need to because it is accepted by all.

    Can you explain CSI so even a novice such as myself can at least understand what I am looking for? Can you explain why scientists are so utterly unconvinced by CSI? What is the weakness that they are missing?

    I know that is a lot, and I don’t really expect an answer. Just wanted to let you know where I am coming from.

  9. Dagoods,
    CSI is too thick a concept to explain in a few sentences. I understand not wanting to read a bunch of books written by people you don’t know, so I went looking around and found an article by William Dembski where he explains CSI. It’s a bit long, but I know you are a quick reader, so it shouldn’t take too much of your time. Dembski originally developed much of the mathematics behind ID theory, so he is your best resource for this topic.

    Having an engineering background, I am familiar with probability theory and information theory at a basic level (I had to take classes on both at GA Tech), and Dembski’s approach made sense to me. I didn’t see anything there that wasn’t pretty standard.

  10. Bill Pratt,

    I wanted to thank you for the link. After perusing it (and reading through a few times) I recalled why Intelligent Design does not resonate as convincing to me.

    Thanks for the discussion.

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