A crystal base for the genetic code

The quantum algebra U-q(sl(2) + sl(2)) in the limit q --> 0 is proposed as a symmetry algebra for the genetic code. The triplets of nucleotides (codon s) in the DNA chain are classified in crystal bases. This construction migh t be compared to the baryon classification from quarks in particle physics, one main difference being the natural order in the state constituents prov ided by the crystal base. An operator ensuring the correspondence codon/ami no-acid is constructed out of the above algebra: two codons relative to the same (respectively different) amino-acid(s) acquire the same (respectively different) eigenvalue(s). The free energy released by base paining in doub le stranded RNA is also computed in our model. (C) 1998 Elsevier Science B. V.