Another modification in the central dogma

How I miss the good old days. And by that I mean high school, when I first learned about the central dogma: DNA begets RNA begets protein. Protein does the job.

As molecular biologists dug deeper, more and more exceptions were revealed. They found that the same piece of DNA could make different RNA's; one RNA could be processed in multiple ways to produce different molecules; protein translation could start at different points; proteins themselves could be modified; DNA could be modified to change the amount of RNA made; tiny little pieces of RNA, some of which come from discarded parts of larger RNA molecules, could modify the amount of translated protein. The list goes on and on.

And now there is one more. In a paper published in Science, Dr. Cheung's group from UPenn report that RNA sequences can differ from the template DNA. The group reached this conclusion by sequencing on average about 2 billion bases of RNA for each of 27 individuals and comparing it to their genome. This kind of work would not have been possible just a few years ago, but in the age of high throughput (or next generation) sequencing ubiquity they are becoming almost regular.

The UPenn group has gone the extra mile to make sure what they are seeing is not an artifact. They used very restrictive criteria, resequenced some of the samples and even looked for peptides that are coming from the modified RNAs. All these controls favor the initial observation.

There is no mention of a mechanism yet, but the observations themselves are exciting. I can't wait to see how this story develops.