Insertion-Deletion P Systems

New computability models, called P systems, based on the evolution of objects in a membrane structure were recently introduced. This paper presents a new variant of P systems with string objects having insertion-deletion rules as the control structure. The use of this control structure is motivated from the DNA Computing area where insertions and deletions of small strands of DNA happen frequently in all types of cells and constitute also one of the methods used by some viri to infect a host. We investigate here the power of this type of systems with less than four membranes, in comparison with the families of CF, MAT and RE.