Well-earned prizes have just been awarded for milestone research on DNA Repair. To quote from the Independent as usual (only because it’s cheap) the contributions of the three winners was as follows:
In their announcement, the committee described how Lindahl “demonstrated that DNA decays at a rate that ought to have made the development of life on Earth impossible”. “This insight led him to discover a molecular machinery, base excision repair, which constantly counteracts the collapse of our DNA.”
Sancar was recognised for his work on “nucleotide excision repair, the mechanism that cells use to repair UV damage to DNA”. That has helped with the treatment of skin cancer, since people born with defects in that repair system will develop skin cancer from being exposed to sunlight. “The cell also utilises nucleotide excision repair to correct defects caused by mutagenic substances, among other things,” the committee wrote.
Modrich’s work demonstrated how the cells corrects errors that occur while DNA is being replicated. “This mechanism, mismatch repair, reduces the error frequency during DNA replication by about a thousandfold,” the committee wrote. “Congenital defects in mismatch repair are known, for example, to cause a hereditary variant of colon cancer.”
Let’s quickly list this work’s utility to the scientific enterprise:
Extends and deepens our knowledge of the natural world √
Has practical application, in this case in life-saving medical advances √
Confirms the paradigm of purely efficient, ateological material causes in science X
Confirms the ruling paradigm of Neodarwinian evolution in biology X
So, big success on the “detail” front – a couple of problems with the “big picture”. Let’s look at the latter.
As soon as you talk about “repair”, just as is the case with “redundancy” , you have entered the world of final causes – teleology. You are talking about a standard, outside the physical structure being repaired, to which it is to be conformed – a target in other words. And goal-setting requires an explanation.
One headline about the Nobel award spoke about “DNA repairing itself”. If one is talking about DNA in terms of separate genes or gene-units, that’s crazy talk – the DNA repair system, assuming it’s entirely gene-based, needs to be intact to work itself, so it could not logically repair itself.
So that headline appears to be suggesting that the genome acts as a single unit, “The DNA” of which one part (the correctly sequenced DNA repair kit) obligingly repairs another part (the broken sequence). That in itself is problematic, for it suggests (a) there is a single indivisible entity, the genome, which would reintroduce the forbidden (and unexplained) idea of form and formal causation. “The DNA” would be another way of saying “The Soul”. Additionally (b) this entails that there is a “norm” or “target” not actually present in the genome itself, towards which the repair process tends. If your assembly program arose in an unplanned fashion, who saved a “correct” version with which it may be compared?
Now, perhaps one might suggest that this target is simply the pre-error sequence, the “last good configuration” on which the repair system operates something like a checksum. But that actually makes not a scrap of difference: something has decided that the “is” of the particular gene sequence has become an “ought”, and “ought” = “final causation”. Like “METHINKSITISLIKEAWEASEL”, such a template is a teleological element that excludes any possibility that the process is truly undirected, except unlike the latter, DNA repair doesn’t make any Dawkinsian pretensions about being an example of the power of randomness – it looks designed anyway, as any honest workmanship looks designed.
Although, ostensibly, the whole thing has been brought into existence by evolution, what has evolved is a very efficient tool for preventing evolution in most cases, and extinction in very many more.
The second big problem in this matter is its effect on the plausibility of Neodarwinian processes (or any other material process we have to hand). Remember that quote from the committee:
Lindahl “demonstrated that DNA decays at a rate that ought to have made the development of life on Earth impossible”.
Here’s the issue: DNA is actually a very unstable molecule. Under ideal conditions, it survives <1m years. Conditions are seldom ideal even now, let alone at the dawn of life, and life requires complete survival of the sequence if one of evolution’s non-negotiable conditions – inheritance of characters – is to be fulfilled. In order for life to develop and evolve you need, and Lindahl has uncovered, “a molecular machinery, base excision repair”. So how, even in principle, is such a complex machinery going to evolve using unstable DNA?
Perhaps, one might wonder, it all happened so long ago (as it must have done for life to get off the starting blocks) that it was a product of the hypothetical RNA world, only later adapted to deal with the unstable chemistry of DNA. But what won’t work with DNA is even less possible with RNA:
While DNA contains deoxyribose, RNA contains ribose (in deoxyribose there is no hydroxyl group attached to the pentose ring in the 2′ position). These hydroxyl groups make RNA less stable than DNA because it is more prone to hydrolysis. https://www.quora.com/Why-is-DNA-stable-but-RNA-is-not
Eugene Koonin felt the need to enlist the multiverse to load the odds sufficiently for DNA replication to have a snowball’s chance in hell of evolving. It’s a good trick to invoke infinite possibilities, because it covers at one bound the extra orders of magnitude required for DNA repair also to evolve within the geological instant it takes for DNA to break down naturally:
Scientists have estimated that under the most ideal conditions, DNA can theoretically survive for a maximum of one million years.
That, of course, ignores replication errors. And the fact that conditions usually aren’t ideal. And that one isn’t supposed to set evolution particular targets and timescales, because it lacks any ambition. If we dismiss the multiverse hypothesis, some would call it a miracle.