The scientists developed transgenic mice in which they can delete some genes from mammary gland cells. Until now, gene deletion was not possible in mammary glands of livestock. Cre-lox recombinase genes originate from bacterial viruses. In such viruses, these genes can naturally cut out DNA sequences. The new approach is directed toward learning to delete specific genes, such as milk protein genes, from cells of a cow's mammary glands.
Scientists can then determine whether specific genes affect mammary gland functions.
The technique also could help medical researchers define genetic contributions to breast cancer, by allowing them to insert or delete various genes in laboratory cell cultures and study them. ARS scientists are evaluating channel catfish diets for optimum growth and disease resistance.