Detection of recombinant DNA from genetically modified papaya

A method using polymerase chain reaction (PCR) was developed to detect the genetically modified (GM) papaya (55-1 line), of which the mandatory safety assessment has not been finished in Japan because of insufficient data. Th e papaya intrinsic papain gene was used as an internal control. The results of PCR amplification of the papain gene segment indicated that a commercia l silica membrane type kit (QIAGEN DNeasy plant mini) was useful for extrac tion of DNA from papaya fruit, but not for extraction from canned papaya fr uit. On the other hand, a commercial ion-exchange type kit (QIAGEN Genomic- tip) provided enough purified DNA for PCR from canned papaya fruit. Compair ed with the parental line and other commercial non-GM papayas, the DNA from GM papaya fruit provided specific amplification bands in PCR with five pri mer pairs (Nos. 2 similar to6) including beta -glucuronidase and neomycin p hosphotransferase II gene-specific ones. On the other hand, the primer pair s recognizing these genes showed false-positive results when we used DNAs f rom canned papaya. Therefore, we recommend that the primer pairs (Nos. 5 an d 6) recognizing the sequences derived from two different species of organi sm should be used in order to detect specifically the GM papaya in canned f ruits.