Transposable elements are at an advantage compared with other DNA sequences. This has led to the generation of transposable systems from a variety of different sources. Once fabricated, these elements can very simply acquire accessory genes, such as those that encode resistance to antibiotics. This can lead to further evolutionary advantages and to their shorter-term importance. It is likely that many new transposable systems will be discovered, owing to the advantages conferred on sequences by transposition, and it is certain that many new transposons that encode varying drug resistance patterns will arise.