Is There a DNA Puzzle in Alberts’ Molecular Biology of the Cell?

Last November, I bought Molecular Biology of the Cell by Alberts (5th edition). I’m a few chapters in, and so far it’s an excellent textbook, I recommend it.
But there’s something that has been intriguing me for months: Once every few pages, seemingly at random, there are groups of 4 red letters inside pointy brackets. At first, I thought it was probably formatting meta-data, some kind of printing accident. But the second time the red letter popped up in a weird place, I noticed that the letters were all DNA letters (T,A,G,C).

Could this be a puzzle? Is this some kind of clever biological joke by the authors?
If it is, what do these code for? Some well-known protein?
It’s a mystery so far.
Update: Unless this is a well-known joke among biologists (it’s a common textbook, after all) and someone tells me about it in the comments or via email, I’ll probably compile a sequence of nucleotide letters long enough for it to be unique and then Google it. I had my “duh” moment and realized there’s no need to go through the whole 1000-page book and compile all of red letters…
April 7, 2008 at 6:07 pm
Insufficient data. If you have all of them or a sufficient number of them, in the proper order, it might be possible to come up with something.
April 7, 2008 at 6:17 pm
Jordan,
You’re right, of course.
Maybe someday I’ll go through the 1000-pages and compile the whole thing (if my curiosity doesn’t fade). But I was kind of hoping that by posting about it, someone who already knows about this would be able to help. It’s a fairly common textbook, so maybe the puzzle/joke is well-known among biologists..?
Or maybe another strategy would be to compile a sequence of nucleotides that is long enough to be unique, and then just Google it and see what comes up. That’s probably the smart way to do it.