title: New clues to a second genetic system.
mesh_terms: D000818:Animals; D004272:DNA, Mitochondrial / Q000266:history* / Q000302:isolation & purification; D004273:DNA, Neoplasm / Q000266:history / Q000302:isolation & purification; D049673:History, 20th Century; D006801:Humans
chemical_list: D004272:DNA, Mitochondrial; D004273:DNA, Neoplasm