"bob" <r.hartley at bio.gla.ac.uk> ha scritto nel messaggio news:a1hbu4$ob6$1 at singer.cent.gla.ac.uk... > Do you mean a mRNA that is constantly produced/available? > > ribosomal RNA springs to mind no rRNA. i mean mRNA present at constant levels during all amphibian development. thanx. Stefano gifalone at tin.it http://web.tiscalinet.it/gifalone