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.
But non-transcribed spacers between genes would seem to accomplish the
same effect with much less cost to the cell. Synthesizing mRNA
corresponding to an intron, cutting it out, and throwing it away is a
mildly expensive operation, and it would seem advantageous to replace it
with something simpler.
Hits to introns can also be deleterious, if they disrupt the splicing
signals--it seems quite easy to silence or botch a gene by preventing it
from splicing correctly.
Mary Kuhner mkkuhner at genetics.washington.edu