The department of biotechnology (DBT) in collaboration with the Hyderabad based Centre for DNA Fingerprinting and Diagnostics (CDFD) has developed a diagnostic kit for rapid detection of genetically modified (GM) traces in food by going to the level of DNA. Earlier a diagnostic developed by the Central Institute for Cotton Research could detect by going only to the level of protein.

“If this new kit is used it can resolve the claims of genetic contamination of conventional crops by GM crops. We can also use this diagnostic kit for checking imported food which may contain traces GM matter,” said the DBT secretary MK Bhan.

The diagnostic kit has been validated for detection from whole or crushed seeds of Bt cotton and Bt rice crops. Both these crops have been genetically modified to express cry 1 Ac and cry 2 Ab transgenes from Bacillus thuringensis and hence called Bt crops. Transgenic crops differ from conventional crops as their genetic make-up has been altered by artificial introduction of a “transgenic cassette”.

The diagnostic kit developed by CDFD in collaboration with DBT employs the polymerase chain reaction technique for rapid detection of five elements in the transgenic cassettes like the promoter CaMV 35S, transgene cry 1 AC or cry 1 Ab, marker gene npt II and the end-signal NOS-T.

The detection of four of these elements is based on primers designed indigenously in CDFD and cross validated by other national laboratories, while the detection of CaMV 35S is based on primers designed to ISO standards, which are likely to be adopted by the Bureau of Indian Standards. “These tests have been shown to be useful in detecting Bt cotton and Bt rice seeds at an admixture as low as 0.4% with non-Bt seeds,” said Bhan.

He said that this diagnostic kit can also be used for Bt brinjal, Bt cauliflower, GM mustard with barnase/barstar gene and GM tomato with osmotin gene. Five institutions in the country namely CDFD, Hyderabad, Central Food Technology Research Institute (CFTRI), Mysore, National Bureau of Plant Genetic Resources (NBPGR), National Institute of Nutrition (NIN), Hyderabad and Indian Toxicological Research Institute (ITRC), Lucknow are now using this diagnostic kit.