candidate: Horizontal gene transfer was first described in Seattle in 1951 in a publication which demonstrated that the transfer of a viral gene into " Corynebacterium diphtheriae " created a virulent from a non-virulent strain , also simultaneously solving the riddle of diphtheria ( that patients could be infected with the bacteria but not have any symptoms , and then suddenly convert later or never ) , and giving the first example for the relevance of the lysogenic cycle .