Two detection methods of genetically modified maize and the state of its import into Japan

We detected genetically modified maize (GM-maize) with two different methods and examined the state of its import into Japan. A method using a cetyltrimethylammonium bromide buffer efficiently extracted DNA. Measurement of the extracted DNA at 260/230 nm and 260/280 nm indicated that the DNA was pure enough for polymerase chain reaction (PCR) amplification. Agarose gel electrophoresis of the PCR amplified products resolved a band at 329 bp for the zein gene and 437 and 522 bp for the introduced genes in Bt11, 619 bp in Event176, 194 bp in MON810 and 231 bp in LIBERTY maize. GM-maize was also detected by an enzyme-linked immunosorbent assay (ELISA) and there was no conflict in the results between the ELISA and the PCR method. However, the PCR method had advantages in distinguishing the lines of GM-maize. GM-maize was contained in the maize seeds imported into Japan between January and March in 2000 and MON810 counted for the largest percentage of the GM-maize.