Porcine nucleic acid sequences flanking potentially infectious porcine endogenous retroviral insertion sites have been identified and isolated. The rechargeable cell is contained within a cylindrical enclosure having a shape such that it can fit into the power source compartment of the clock, and having contacts allowing it to be substituted for the conventional electrochemical power source. A peripheral switching gate electrode is formed on the first gate insulating layer of the peripheral portion, and a pixel switching gate electrode and a driving gate electrode are formed on the first gate insulating layer of the pixel portion.