Re:junk genes was a junk idea (Score 1)

(1) Non-biologists, often ideologically based such as the Stephen Jay "Gouldians", gave the popular media writers the greatly mistaken impression that natural selection was a weak force and there was considerable randomness, "junk", in the genome. Due to the astonishingly massive influence of the Gouldians most evolutionary biologists just plain gave up even trying to communicate with journalists. Hence in the popular media the idea of junk DNA has persisted long, long after many evolutionary biologists have considered the term a joke. (An interesting read in this context is the Ridley chapter on "mutational meltdown"- If there aren't very powerful forces (i.e. selection pressures) maintaining adaptations then the high mutation rates would rapidly devolve them.)

      (2) It was written in one of these threads that stretches with more junk are more likely to be translated. As one of the principal theoretician-mathematicians of evolutionary biology once spoke for the sake of discussion (John Maynard-Smith) ...selection at the level of the gene is say about 50 times that of selection at the level of the organisms, which in turn is about 50 times that at the level of the (gene pool). (I would say now perhaps more than 300 times that at the level of the gene pool, but it gets definitional.) Some thirty years ago JMS used that to argue for trying out hypotheses at the level of the organism in preference to hypotheses about group level selection. This points in the direction of considering hypotheses such as - perhaps the reason stretches with more junk DNA are more likely to be translated is because the junk DNA is "sopping up" genetic elements (RNA etcetera) that are trying to inhibit the protein-level expression of those stretches of genes. By the way, as with all metaphors they ultimately break down because ultimately you're comparing to different things. I generally like computer metaphors, but I find that at the abstract level I try to communicate with people about the subtleties of evolution computer metaphors often can be more of a hindrance than help. Such as with respect to effects of selection at the genic level as one example.

  (3) How expensive is DNA? I read somewhere ages ago that in organisms such as humans approximately 1% of the total metabolic budget is expended in replication DNA molecules. As a total, that is appreciated by evolutionary biologists and physical anthropologists as being a very powerful selection pressure. (Note again the seriously deleterious effect of those who argued natural selection was a weak force in evolution.)

    (4) Grym wrote-
As an aside, I suspect we'll start to see a more integrated approach to genomics once the relatively low-hanging fruit of the one-gene --> one-protein research lines are throughly covered. However, I wouldn't expect such things to happen in our lifetimes given the difficulty of that aforementioned task and the sheer profitability of more conventional approaches. But what do I know? I'm "just a biologist." =P

      It has turned out that I've been correctly highly sceptical of the "bio-technology revolution" in terms of application. (...Because of a deep appreciation of the ability of selection pressures to shape and maintain massive amounts of biological complexity.) Still, I've been amazed at how rapidly genetic technologies have advanced in since 1992. So I'm much more optimistic on this point about covering all research associated with "one-protein research lines". In fact, I think in about another five years...

    inkwiztor, aka harpersnotes