Figure 7From: On origin of genetic code and tRNA before translationPossible tRNA precursors: variants of (11 + 7 = 18) elongation. Variant A represents the canonical acceptor arm. Variant B could also be used in primordial translation. Variant C might represent even the earlier stage of an RNA replisome [45] with pre-tRNAs functioning as donors of trinucleotides for growing complementary RNA strand during replication.Back to article page