Junk DNA and Evolution

Does evolution depend on a lot of junk DNA?

Does evolution depend on a lot of junk DNA?

In my previous post, I reviewed the book Naturalism and Its Alternatives in Scientific Methodologies. At the end of the review, I mentioned that the book suggested a conclusion for the famous ENCODE experiments that I had never considered. In case you are unaware, ENCODE is an international collaboration of scientists who want to find out exactly how much of the human genome is actually used by the human body. In 2012, they made the startling announcement that more than 80% of the human genome has at least one biochemical function. This flatly contradicts the evolution-inspired notion that the vast majority (up to 98%) of the human genome is composed of “junk DNA” and is not used for any purpose. Evolutionists have generally dealt with ENCODE’s conclusion in one of two ways. Some say that ENCODE’s definition of “function” is too broad, so what they call “functional DNA” is not really functional. Thus, the vast majority of human DNA is still “junk.” Others suggest that the concept of “junk DNA” isn’t vital to evolution to begin with, so ENCODE’s results (correct or incorrect) do not really relate to evolution.

I have always considered that those in the latter group have a very weak case. As Dr. John Sanford demonstrated a while ago, the “gold standard” digital simulation of evolution (Avida), requires at least 85% of the starting genome to be junk in order to produce any significant evolution. However, while reading Chapter 13 of Naturalism and Its Alternatives in Scientific Methodologies (written by Salvador Cordova), I learned about another argument against the idea that evolution doesn’t depend on junk DNA. It comes from evolutionist Dr. Dan Graur, who says quite plainly:

If ENCODE is right, evolution is wrong. (p. 234 of Naturalism and Its Alternatives in Scientific Methodologies)

Even though I am a creationist, I would never make such a strong statement, but Dr. Graur thinks it is obvious. Why? According to Chapter 13 of Naturalism and Its Alternatives in Scientific Methodologies, it’s because each generation suffers from genetic mutation. In order for natural selection to “weed out” most of the deleterious mutations, each generation needs a certain number of individuals from which natural selection can choose. The more possible deleterious mutations, the more individuals natural selection needs in each generation.

Now, if the vast majority of the human genome is junk, then the vast majority of mutations are not deleterious, because they occur in the unused, junk portion of the genome. As a result, we don’t need to produce many offspring in order to give natural selection enough choices so it can keep most of the deleterious mutations out of the gene pool. However, if the vast majority of the genome is functional, then there are a lot of deleterious mutations, so we need to have more offspring to give natural selection what it needs to weed them out. According to Graur, if ENCODE is right, each person needs to have 3×1019-5×1035 children in order to keep those deleterious mutations from piling up in each generation. Obviously, that’s not possible, so if ENCODE is right, evolution is wrong.

Of course, as a creationist, I like Dr. Graur’s conclusion. Indeed, it fits in very well with Dr. John Sanford’s view that the human genome can only be thousands of years old specifically because natural selection cannot weed out the deleterious mutations. However, I am willing to consider a third option. Perhaps Dr. Graur is wrong. Perhaps the human genome is more resilient than he thinks. Unfortunately, I really don’t know. As I said, I hadn’t previously heard Dr. Graur’s argument. I have since read about the concept on which it is based (mutational load), and his calculations seem correct. However, I really doubt that I understand the details well enough to spot any serious errors.

I am wondering if any of you have heard this argument before. If so, what do you think about it?


  1. Wilbur Nelson says:

    Just ball-parking it with no expertise: seems like the population sizes would have to be enormous in any case. Just to have something to select. Hundreds of millions of bacteria might okay for an adequate selection size — but you can’t do that with blue whales or elephants. (And then extrapolate that to **every** species of mammals alone would seem to consume the planet several times over.)

  2. JoeCoder says:

    This has been my first argument against evolutionary theory for several years now. I’ve debated it with dozens of biologists and a few evolutionary biologists–some well known in the origins debate. There are probably two dozen possible objections but they are all easily answerable. I’ve found this argument steadfast and reliable.

    1. JoeCoder says:

      Larry Moran also seems to accept half of this argument:

      “if the deleterious mutation rate is too high, the species will go extinct… It should be no more than 1 or 2 deleterious mutations per generation.”

      Of course Moran’s position is that almost all DNA is junk. Susumu Ohno had a similar realization back in 1972:

      “the moment we acquire 10^5 gene loci, the overall deleterious mutation rate per generation becomes 1.0 which appears to represent an unbearably heavy genetic load… at the most, only 6% of our DNA base sequences is utilized as genes”

      He gets up to 6% by assuming many genes are duplicates of one another. And by “genes” in this context he is talking about a functional region of DNA, not necessarily a sequence that is specifically protein coding.

      [1] http://sandwalk.blogspot.com/2014/04/a-creationist-tries-to-understand.html
      [2] http://www.junkdna.com/ohno.html

  3. Cher says:

    How can we be sure which is junk dna? I know I’m comparing apples to oranges here, so I need some help: In the past, scientists thought the appendix and the tonsils were not useful or necessary and were “left over” from a previous time. Then we discovered they are important for our immune system. So, how can we be sure about DNA being junk?

    1. Jay Wile says:

      That is an issue, Cher. A small percentage of DNA codes for proteins, and that is easy to determine. Sometimes, scientists can determine how a stretch of DNA that doesn’t code for proteins works, such as what was done with introns and how they do alternative splicing. Other times, we can show that a stretch of DNA that was thought to be broken actually isn’t broken, such as what has been done with some pseudogenes. However, teasing out the specific function of each stretch of DNA will take a long, long time. What ENCODE did instead was to see what stretches of DNA were translated into messenger-RNA and exported from the nucleus. Their argument is that the cell wouldn’t spend the effort and energy on that process if the stretch of DNA wasn’t used. Thus, by searching for the messenger-RNA that exists outside the nucleus and connecting it to a stretch of DNA, you can at least determine what stretches of DNA are read by the cell and taken out of the nucleus. Assuming that means functionality, you can determine what parts of the genome are functional.

  4. John D. says:

    It does seem that evolutionists need something besides a pure Neo-Darwinian explanation. I’m surprised there aren’t more scientists suggesting a cognisant genome. If I were an evolutionist, who refused to explore the idea of a Creator, I would lean towards this idea.

    If I were not a Creationist I would contend life, in and of itself, has the ability to problem solve. This is an inherent quality of biological systems down to the smallest parcel. Life is not accidentally solving problems, it is purposefully doing so.

    1. You might be interested in Perry Marshall’s book Evolution 2.0 – he seems to be suggesting something in that direction and seems to think that more scientists are beginning to think this way, i.e the recent “Royal Society” conference about “new trends in biological evolution”.

      Of course, as Marshall himself illustrates, it’s hard to recognize these problem-solving abilities (i.e. as Dr. Wile suggests, “Perhaps the human genome is more resilient than he thinks”) without also recognizing their implications for a purposeful Creator – even within an evolutionary framework.

      1. Nicolás Vera says:

        Indeed if life had the ability to engineer itself it would point EVEN more towards design (because it would be not only a program, but a program who write programs, which is even more complex), indeed towards exquisite and ingenious design.

Leave a Reply

Your email address will not be published. Required fields are marked *