[quote=Captain Jordan]
What I'm surprised by is that they couldn't come up with any better letters than X and Y. I mean, DNA is already GATC, why not add in P and V? Or N and E? Just something more creative than X and Y is all I'm asking for.
[/quote]

Perhaps they chose X and Y because they are obviously artificial. I suppose if they chose some other letters they would have to justify it somehow by coming up with a matching name, such as guanine for G or thymine for T. X and Y, however, are so arbitrary that they can be used to label anything. Of course, that's avoiding creativity.