I'll go out on a limb and say that "T" is the right answer until Claude tells us otherwise : ). I think Chelsea basically wrote up the (first-level) "confirmation" messages (except for Glyph #6, maybe ; ) ) for when we get them right. While RNA is of course important, it's DNA that's the genetic code, which makes living things what they are (I _think_ that's true for all organisms). So that would take "U" out of play...but only for this part of the puzzle (solving central glyph symbols). So keep "U" in mind G'Kar, it might show up once we get all the central symbols : )!