Fig. 2
From: The primordial tRNA acceptor stem code from theoretical minimal RNA ring clusters
Heatmap of pairwise D3 distances among 25 RNA rings, ordered by increasing rank of mean percentage of tRNAs (with the same cognate amino acid as the RNA ring) with primitive code in their acceptor stem (averaged across kingdoms as per data in [54]). The tRNAs considered in [54] with primitive acceptor stem code have cognates A, D, G, V. The heatmap shows these clusters (blueish colors) with RNA rings 3, 4, 8 and 9 (cognates S, Pyl, R and Sec)