>>>>> "Mary" == Mary K Kuhner <mkkuhner at phylo.genetics.washington.edu> writes:
Mary> In article <4q9fn7$p4k at bolivia.it.earthlink.net> MIKE LAMB <mikejonlamb at earthlink.net> writes:
>> Here is one intron benefit: Cancer prevention aid. Introns can take
>> hits from chemical carcinogens. These hits might otherwise hit and
>> mutate an exon causing more damage. The more introns there are, the
>> fewer damaging mutations occur.
Mary> But non-transcribed spacers between genes would seem to accomplish the
Mary> same effect with much less cost to the cell. Synthesizing mRNA
Mary> corresponding to an intron, cutting it out, and throwing it away is a
Mary> mildly expensive operation, and it would seem advantageous to replace it
Mary> with something simpler.
I've wondered about the cost to the cell of introns -- what happens to the intron
strand once it is spliced out? Is it used for *anything* in cell metabolism?
Mary> Hits to introns can also be deleterious, if they disrupt the splicing
Mary> signals--it seems quite easy to silence or botch a gene by preventing it
Mary> from splicing correctly.
It might cause it to be expressed... Also, introns may play a role in the folding
of chromosomes -- they arn't scrunched up randomly...
I used to think that my brain was the most wonderful organ in my body.
Then I realised who had been telling me this...