'Junk DNA'

Junk DNA: Dan Graur (junk!), ENCODE team (not junk!), and the science media

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Graur’s latest claim that 75% of the human genome is non-functional has attracted a lot of digital ink. Pop science loves that sort of thing.

From Kerry Grens at the Scientist:

Up to 25 percent of the human genome is critical, while the rest has no function, according to a study published July 11 in Genome Biology and Evolution. The estimate, generated by looking at fertility rates and the expected frequency of deleterious mutations, contradicts a 2012 claim from a large international group called ENCODE, which estimated that 80 percent of the genome is functional.

“For 80% of the human genome to be functional, each couple in the world would have to beget on average 15 children and all but two would have to die or fail to reproduce,” writes Dan Graur, an evolutionary biologist at the University of Houston, in his study.

Graur’s model is built on the idea that fertility rates reflect how much of the human genome is vulnerable to deleterious mutations, and therefore functional. If most of the genome is functional, then people would have to have a lot of babies to maintain the human population and make up for the decreased chances of survival that accompany a greater possibility for harmful mutations. … More.

From Michael Le Page at New Scientist:

After 20 years of biologists arguing that most of the human genome must have some kind of function, the study calculated that in fact the vast majority of our DNA has to be useless. It came to this conclusion by calculating that, because of the way evolution works, we’d each have to have a million children, and almost all of them would need to die, if most of our DNA had a purpose.

But we each have just a few children on average, and our genetic health is mostly fine. The study therefore concludes that most of our DNA really must be junk – a suggestion that contradicts controversial claims to the contrary from a group of prominent genomics researchers in 2012. More.

This all sounds too clever by half.

See also: The dangers of bad paradigms and the need for evolutionary teleonomy (Johnny Bartlett):

This paper represents one of the worst instances of how the Modern Synthesis (colloquially known as neo-Darwinism) can blind someone to thinking, and why the concept of Evolutionary Teleonomy is desperately needed in evolutionary biology.

Graur’s Campaign against ENCODE

Graur has been a long-time critic of encode. In fact, Graur has been on record as saying that, essentially, if ENCODE is right, evolution is wrong (his earlier paper criticizing ENCODE for being an “evolution-free gospel” can be found here). At his personal website (very bottom), Graur shows a picture of his baby granddaughter, where Graur’s own caption for the photo is “My granddaughter, Lilla Keshet Graur, gives ENCODE the finger”. More.


7 Replies to “Junk DNA: Dan Graur (junk!), ENCODE team (not junk!), and the science media

  1. 1
    rvb8 says:

    I fail to see how the junk DNA argument should in any way be discussed by Intelligent Designers.

    Look at your title; ‘Intelligent Design’.

    If any part of the genome sequence is a non-coding remnant, then the designer has installed something redundent; S/He is not intelligent.

    I have read that Encode says a figure as high as 80% of the human genome is essential and without this DNA, human life could not go on. Many IDists applaud this very high figure.

    Why? Doesn’t it simply mean your designer installed 20% of junk DNA.

    The figure for ‘junk’ is of course much higher than 20%, and as our techniques for following protein coding, and then uncovering what phenotypes (if any) these genotypes lead to, this higher figure will be further strengthened.

  2. 2
    Seversky says:

    According to Larry Moran’s blog post, if there’s somewhere between 75 to 150 mutations per generation there could be from 4 to 40 that could be detrimental. If the whole of the genome were functional then wherever they occurred they would cause damage, perhaps more than could be survived. If only 25% of the genome is functional, there’s a much better chance that most, if not all, of those mutations would pop up in non-functional regions where they’d do no harm at all. Maybe that’s why we’re still around.

  3. 3
    ET says:

    If so much of our genome is junk then evolutionary biologists must be some of the stupidest people on earth for not being able to figure out how we evolved. But I digress- histone octamers argue against the claim that the majority of our genomes are junk. Did those histone octamers evolve to spool up the junk and package the DNA so that it the functional parts could be readily accessed? That seems like planning was required to do so.

    Only ignorance says the majority of our genomes are junk. But then again only ignorance says that natural selection is a designer mimic.

  4. 4
    EricMH says:

    @Seversky There is a lot of genetic disease, so you may be right.

    Population genetics suggests humans, and organisms in general, are devolving, not evolving.

  5. 5
    DATCG says:

    This has been addressed as well by geneticist Dr. John Sanford, in his book published 2008, updated 2014.
    Genetic Entropy

    site quotes…

    Genetic entropy is most easily understood on a personal level. In our bodies there are roughly 3 new mutations (word-processing errors), every cell division. Our cells become more mutant, and more divergent from each other every day. By the time we are old, each of our cells has accumulated tens of thousands of mutations. Mutation accumulation is the primary reason we grow old and die. This level of genetic entropy is easy to understand.


    There is another level of genetic entropy that affects us as a population. Because mutations arise in all of our cells, including our reproductive cells, we pass many of our new mutations to our children. So mutations continuously accumulate in the population – with each generation being more mutant than the last. So not only do we undergo genetic degeneration personally, we also are undergoing genetic degeneration as a population. This is essentially evolution going the wrong way. Natural selection can slow down, but cannot stop, genetic entropy on the population level.

    So yes, there might be a downward drift, not upward.

  6. 6
    Peer says:

    It is now very clear that a major part of the socalled junk is not junk. In particular the activity of socalled ERVs, LINES and SINES (together they make up about half of the human genome) is required for early embyonic development. Knocking the activity down, using siRNAs, the developement cannot go beyond the very early stages. It is so important to conserve the system, that amplification mechanisms have been built in these genetic elements.

  7. 7
    bill cole says:

    The junk DNA discussion rides on the assumption that we can get accurate measurements of generational mutation rates. I think this is highly suspect because of the accuracy and frequency (how often it is implemented) of the DNA repair mechanisms. You can measure 50 generational mutations at point A but they can then be eliminated at point B by the repair mechanism. The confirming measurements are based on the assumption of orthodox common descent and looking at genetic change.

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