GM cows produce hypoallergenic milk Researchers from AgResearch, an independent company, used strands of genetic material known as RNA to silence the genes responsible for producing the allergenic protein. They tested the technique on mice before producing a female calf, and stimulated it to produce milk using hormones. Writing in the Proceedings of the National Academy of Sciences journal, the authors said the genetic engineering technique could be used to modify other traits in livestock. Prof Bruce Whitelaw, Professor of Animal Biotechnology at Edinburgh University, who was not involved in the study, added: "This is notable since it represents one of the few RNA interference success stories in mammals and offers a good example of how these technologies can be used to provide alternative strategies to current manufacturing process. Time will tell how widely applicable RNA interference will be in GM livestock - but this is certainly a milestone study in this field.