One of these new genes was for making lysostaphin protein.
Fibroblasts are a type of general, all-purpose cell.
Scientists then fuse the gene-altered fibroblasts to unfertilized cow eggs. This actually is done after the scientists first scoop out the eggs' own DNA so that the fibroblasts' DNA can move, along with its new genes. Only about 60 percent of these fused cells actually survive, and start dividing like a normal fertilized embryo.