What I love most about science in general, and genetics in particular, is when new findings upend everything we thought we knew about something. That was so in 1977, when "intervening DNA sequences" – aka "introns" – were discovered to interrupt protein-encoding genes.
Sometimes, we discover new ways that organisms do things. Changing gene expression – the set of genes that are transcribed into mRNA and then translated into proteins under a particular circumstance – is how organisms rapidly respond to a challenge. For an octopus, that might be a sudden plunge in water temperature, which slows enzyme activity.
But some species control genetic responses another way – via RNA editing. Changes in one of the four types of nitrogenous bases of an mRNA alter the encoded protein in ways that alter the protein's function.
In a new report in Cell, Joshua Rosenthal of the Marine Biological Laboratory at Woods' Hole and Eli Eisenberg at Tel Aviv University describe how the cephalopods – octopi, squid, and cuttlefish – change mRNAs in ways that alter enzymes. Because the edits are in RNA, and not DNA, they are fleeting. "We're used to thinking all living things are preprogrammed from birth with a certain set of instructions. The idea the environment can influence that genetic information, as we've shown in cephalopods, is a new concept," said Rosenthal.
To continue reading, go to DNA Science, where this post first appeared.