The researchers took an E. coli gene that makes the enzyme phytase and a mouse gene that controls the production of a protein secreted in the salivary glands and made a new gene. That composite gene was inserted into the nucleus of a one-celled mouse with a microscopic needle. The gene allows the mouse to make phytase in the salivary gland and secrete it into its saliva, where it is swallowed with food. The phytase releases organic phosphorus in the rodent's gut that can be absorbed by the bloodstream. In fact, he added, phosphorus reductions may even be greater in farm animals because mice recycle phosphate, which may make the decrease of phosphorus levels in their manure appear less substantial.
Animal waste is a leading source of phosphorus pollution from agriculture.
Phosphorus pollutes surface and groundwater and promotes the growth of algae in rivers, lakes and streams, reducing available oxygen to fish and aquatic life. Two years ago, Phillips, Forsberg and Golovan announced they had produced transgenic pigs that carry the same composite gene. They have been conducting research trials on the animals and are expected to publish results in the next few months. It also sets the framework for future work involving other transgenic farm animals.