title: Doublet frequencies in the DNA of genetic code limit organisms.
mesh_terms: D000818:Animals; D001483:Base Sequence; D005075:Biological Evolution; D003062:Codon / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D004269:DNA, Bacterial / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D003854:Deoxyribonucleotides / Q000032:analysis; D005815:Genetic Code; D008433:Mathematics; D008954:Models, Biological; D013045:Species Specificity
chemical_list: D003062:Codon; D004269:DNA, Bacterial; D004279:DNA, Viral; D003854:Deoxyribonucleotides; D004247:DNA