The puzzle of RNA recombination

For more than three decades, RNA recombination remained a puzzle and has on ly begun to be solved in the last few years. The available data provide evi dence for a variety of RNA recombination mechanisms. Non-homologous recombi nation seems to be the most common for RNA. Recent experiments in both the in vitro and the in vivo systems indicate that this type of recombination m ay result from various transesterification reactions which are either perfo rmed by RNA molecules themselves or are promoted by some proteins. The high frequency of homologous recombination manifested by some RNA viruses can b e easier explained by a replicative template switch. (C) 1999 Federation of European Biochemical Societies.