17 JUNE 1989, Page 24

Etymology

Sir: Surely the drug Retrovir is named from the technical term for the Aids infective agent, which is a retrovirus; that is, a virus which transcribes genetic mate- rial from RNA to DNA, and not vice versa as used to be thought universal (City and Suburban, 10 June). I don't imagine Well- come would deliberately perpetuate the cruel pun which, alas, one can make of the name.

Richard Browne

8 Southbrook Close, Langstone, Havant, Hampshire