A chip the size of a human fingernail has been developed by a company in Shanghai to detect within four hours whether agricultural produce has been genetically modified. The chip is just one centimetre in size and could identify as many as 40 different genes. Huang Xinhua, an executive with Shanghai Boxing Gene Chip Corporation, the chip maker, said the chip could screen out transgenic soybeans, corn, cotton, rapeseed and other products, reported the Xinhua News Agency.