Highly conserved, but how important?
Today Pharyngula takes a break from his exhaustive documentation of the existence of wackos and evil-doers among religious and political conservatives -- who would have guessed? -- to discuss highly conserved non(protein)coding DNA. It seems reasonable that if a DNA sequence is highly similar between humans and fish, whose last common ancestors lived way back in the good old days, then it's probably doing something important. But a paper I discussed earlier showed that highly conserved noncoding regions can sometimes be deleted without any apparent ill effects. Of course, this is also true of some protein-coding genes; we apparently have a lot of backups. Actually I'm not sure computer and circuit-board analogies are that useful.