Friday, September 7, 2012

Junk's not junk

For ages, it has been said that humans use only a small percentage of their cerebral potential. Personally, I've always been wary of this kind of evaluation. The experimental evidence for such a conclusion is obscure, to say the least. What would it mean, at a practical level, if my cerebral performances were suddenly doubled, say? Would I understand twice as many things as I did previously? Would I have a vision of our human existence that was twice as deep as my old way of looking at things? Would I be capable of thinking twice as rapidly as I used to? Would I be able to master new fields of learning? Would I now have a clear perception of things that once appeared fuzzy in my mind? Would I be clearly conscious of the fact that I was twice as smart as I used to be? Frankly, I've always imagined all that extra yet-unused brainpower as akin to the legendary multiple lives of a cat. It sounds like a great idea... up until you try to imagine what it might mean in practice.

More recently, I've often been similarly wary, indeed stupefied, when I've heard geneticists talk of so-called junk DNA. The idea is that only some 2 per cent of our precious genetic heritage plays an essential role in the synthesis of proteins and operational cells and organs. The remaining 98 per cent would appear to be biological "dark matter" that simply comes along for the ride, in an almost parasitical fashion.

Once upon a time, when scientists told us that the human body was largely composed of water, I used to wonder whether it might be possible to "dry out" a human being, by removing magically all this surplus wetness. Would the waterless creature work just as well? Or would he simply shrivel up and die like a fish discarded on a sunny riverbank? In a similar way, I wondered naively about all that junk stuff that I was carrying around with me. If it were completely useless in my survival, then we might imagine a zapping device capable of eliminating everything that wasn't essential. Normally, after being zapped, I would be reduced to a dwarf, with only 2 percent of my original volume, but I would remain just as smart as before... or even much smarter, if I decided to combine the junk-DNA-zapping with a foolproof method for gaining control of all my unused brainpower. I would be transformed into a mighty midget! As Hamlet said:
I could be bounded in a nutshell, and count myself a king of infinite space, were it not that I have bad dreams.
We adepts of genealogical research have always been stalwart admirers of junk DNA. Funnily enough, although specialists affirmed that all this vast quantity of code achieved nothing of a useful nature, it was nevertheless the object of mutations. And the analysis of such mutations in Y-chromosomes has enabled us to trace paternal lineages. So, the junk hasn't been as totally junky as you might imagine. For example, if ever I were able to discover the identity of the first fellow in England who procreated dozens of generations of descendants named Skeffington (Skevington, Skivington, Skyvington, etc), then my junk DNA would be far more precious, for me, than all the crown jewels in the Tower of London.

Meanwhile, researchers concerned with the human genome have just announced that it is high time for us to realize that so-called junk DNA is anything but that. These researchers have been participating in a huge research project known as Encode: a consortium, based at the University of Santa Cruz in California, that is building a huge databse of the various bits and pieces of the genome.

DNA strings that don't code the synthesis of proteins take care of a multitude of necessary behind-the-scenes activities such as switching genes on or off, and regulating the context in which genes carry out their functions. Suggesting that DNA segments are "junk" simply because they don't have a star role in the coding of proteins is as silly as saying, for example, that the fabulous Avatar movie was created solely by a single director, or a pair of actors, and that all the background support was of no importance.

I liked the comments of an observer who referred to research in genetics by means of a sporting metaphor. "We're still in the warm-up, the first couple of miles of this marathon."

1 comment:

  1. Found your blog while Goggling to see if anyone had yet connected the now "non-junk" junk DNA to previously unknown Y-chromosome "Junk DNA" functionality. This was the only real hit! I'm amazed that no one seems to be talking about this since I'd expect it to have potential as a real "game changer". I follow several big genetic-genealogy forums and not a peep on them yet.

    Science seems often to have a tenancy to be overly impressed with what it thinks it knows, ignoring that there is always even more it doesn't. The notion that nature would pass useless DNA through untold generations always seemed laughable on it's face. Perhaps the STR & SNP mutations which up until now have been assumed to be of no more use than a convenient to gauge relatedness will now prove to have some functional effects.