  The idea of the evolution of the genetic code from the CG to the CGUA
alphabet has been developed further. The assumption of the originally triplet
structure of the genetic code has been substantiated. The hypothesis of the
emergence of stop codons at the early stage of the evolution of the genetic
code has been additionally supported. The existence of strong and weak letter
doublets of codons and the symmetry of strong doublets in the genetic code
table, discovered by Rumer, have been explained. A hypothesis concerning the
primary structure of the first gene and the first protein has been proposed.
