MODEL RELEASED. Cloning research. Scientist removing oocyte cells from the ovaries of a domestic cow (Bos taurus) by endoscopy. The oocytes will be used in cloning research to carry donor genetic material to create a clone. Once an oocyte has been extracted, it has its nuclear material removed. The empty oocyte is filled with nuclear material from a body (somatic) cell of a donor animal. The resulting cloned oocyte is cultured to the blastocyst embryo stage before being implanted into a foster cow for pregnancy. Clones of valuable domestic cows and the gaur (Bos frontalis), an endangered species related to the cow, have been created by this method.