[RNA-fragments, necessary primers for the in vitro replication of DNA].

Partial degradation of ribosomal RNAs (E. coli rich in purine nucleotides) by different ribonucleases gives rise to the appearance of several families of RNA-fragments which after separation on "Sephadex G 25" were analyzed for base ratio, size and biological activity. In the presence of DNA dependent DNA polymerase, RNA-fragments act as primers for in vitro replication of DNAs from numerous sources.