🚀 go-pugleaf

ulan@cbl.cees.edu (Robert Ulanowicz) wrote:

>baez@guitar.ucr.edu (john baez) writes:


>>>It's pretty highly conserved, so calling it "junk DNA" is probably
>>>just due to the hubris of biologists, IMHO. 

>>I'd love to know more about that.  What are some hypotheses for what its
>>role might be?

>IMHO, it's "role" is rather indirect. That is, it isn't doing anything 
>mysterious at the current time. It serves as a "resevoir" of potential 
>repretoires that could be induced into a specific role in response to a 
>novel perturbation or set of circumstances. Without such a resevoir there 
>could be no adaptability. An organism perfectly suited to its 
>current environment is one that will destruct at the next change in that 
>environment.

>My experience has been that most people cling to maximal efficiency 
>arguments for some personal or ideological reasons. But there's a lot of 
>noise out there, and organisms that can't hedge their bets are doomed. 
>Simple as that. (Or is it?)

You may be right, but it's my understanding that sequences in much of
the non-coding DNA have been more highly conserved than would have
been predicted by the replication error rate (this is rather crucial,
does anyone have any numbers?). If this is so, then it implies that
there is some sort of selection pressure to keep some aspects of these
sequences. We're not necessarily talking about *maximal* efficiency,
here, but postulating non-coding DNA to be junk does imply that we're
operating at about 1% efficiency.

Ken Muldrew
kmuldrew@acs.ucalgary.ca