life Opinion Piecemeal Buildup of the Genetic Code, Ribosomes, and Genomes from Primordial tRNA Building Blocks Derek Caetano-Anollés 1 and Gustavo Caetano-Anollés 2,* 1 Department of Evolutionary Genetics, Max-Planck-Institut für Evolutionsbiologie, 24306 Plön, Germany; caetano@evolbio.mpg....