['< sod > using insights gleaned from [ [ archaea | archaeal ] ] genomes, erives elaborated and described a [ [ stereochemistry | stereochemical ] ] model of " proto - anti - codon rnas " ( pacrnas ). < ref name = pacrna / > the pacrna model ascribes a predetermined combined origin for the universal [ [ genetic code ] ] (\'\' i. e.\'\', the acronym codon table ), the biogenic amino acids, and the their exclusive [ [ homochirality ] ] in life. the model implies that early [ [ rna world ] ] was an aminoacylated rna world and that [ [ proteinogenic amino acid ] ] s arose because mainly of compatible interactions with nucleotide - based polymers. the pacrna model explicitly lists possible interactions between various anti - codon di - nucleotide and tri - nucleotide sequences and specific gm amino acids. when the individual nucleotides are d - ribose based, l - amino acids acids are preferred. the pacrna model may also explain why extant [ [ trna ] ] s are heavily [ [ current rna modification database | modified ] ] in all [ [ three - domain system | three domains of life ] ]. < eod > < sod > using insights gleaned largely from [ [ archaea | archaeal ] ] genomes, erives elaborated and described yet a [ [ stereochemistry | stereochemical ] ] model of " proto - anti - codon rnas " ( pacrnas ). < ref name = pacrna / > the pacrna model ascribes a predetermined combined origin for the universal [ [ genetic code ] ] (\'\' i. e.\'\', the codon table ), the biogenic amino acids, and the their exclusive [ [ homochirality ] ] in life. the model implies that early [ [ rna world ] ] was an aminoacylated rna world and that [ [ proteinogenic amino acid ] ] s arose because of such compatible interactions with nucleotide - based polymers. the pacrna model explicitly lists possible interactions between various anti - codon di - nucleotide and tri - nucleotide sequences and different amino acids. when the nucleotides are d - ribose based, l - shaped amino acids are preferred. < eod >']