IF the genetic code is basically just a
pyrimidine - hydrophobic/
purine - hydrophilic, split:
Then we may go further with the idea and these clues
for codons
1. Every base pair can work with two exception, 2
pyrimidines (U,C), or 2 purines (A,G). U can bond
with A or G
I (amodified form of A) can form with U,C, or A
2. The code may well be based on amount of pyrimidine or
purine. IF in 2nd position, UC/pyrimidine = phobic,
GA/purine = philic
3. But if U in center position then C cannot be on either
side of that same strand or you have the danger of dimers
from UV. Thus no CUC codon early on.
4, It would be doubtful to have U in first position when
UAG, UGA, UAA all code for stop. This suggest the U + a
purine rule for stop.
4. Pyrimidine in 2nd position = phobic, but if it is also in
first, more phobic and 3rd most phobic
5. Purine in 2nd position = philic, but if it is also in
first, more philic, and 3rd most philic.
6. The most easily made base in prebiotic experments seems
to be in this order, purine A, purine G, pyrimidine U,
pyrimidine C. Note the prevalence of ATP
7. The initial fit in all 3 positions was probably not the
WC base pairing we're used to (A/U, G/C) The fact that we
have I as a replacement for A suggests that A was first
bound to U, and perhaps C and other A's
8. The U can base pair to the G in wobble position now. It
probably could or did in all 3 positions at the start.
10 When there is wobble in 3rd position it is always either
a purine (A or G) or a pyrimidine (U or C) There can never
be a wobble that offers one of each in third position.
11 Stacking of 3 purines may be the most stable. and perhaps
best suit it for hydrophilic behavior.
9. Stacking of 3 pyrimidines may be the least stable and
perhaps best suit it for hydrophilic behavior.
I contend that somehow these and other clues suggest how
first coding set up a philic/purine and phobic/pyrimidine
coding system that evolved to the code we have now.
Comment?