One of the major controversies around GM foods is the risks of propagation in the nature of manipulated genes.
The transgenic maize of the Novartis group, for example, produces an anti-Arab toxin, but along with the toxin-producing gene, it also contains an anti-ampiziline gene, the antibiotic of the penicillin family. This gene is an inactive gene in corn, but if the bacteria assimilate and activate it, it can easily spread to animals and humans, causing disease resistance.
British researcher John Heritage has studied how this plant gene is transmitted to bacteria and bacteria to chickens and has seen that the "harmful" gene has not been activated in bacteria or chickens. The results are provisional and other animal species are analyzed