mothers and, after birth, traced the tissue contribution of each cell type made by studying the coat color. Her cell fusion technique was successful where others had failed due to the choice to remove the zona pellucida with pronase treatment, rather than physically. Since 1967 Mintz has created more than 25,000 offspring using this technique. Mintz demonstrated that teratocarcinoma tumor cells could be reprogrammed to contribute to a healthy mouse when combined with normal mouse embryo cells through eight years of experiments using some of the first pluripotent stem cell cultures ever made. Mintz and Rudolf Jaenisch published a technological breakthrough in 1974. Jaenisch was a post-doctoral researcher at Princeton University at the time. He was interested in why only certain types of cancer occurred when he injected adult mice with viruses. Inspired by Mintz's earlier work, he wanted to know whether injecting virus into early-stage embryos would result in the DNA being incorporated, and what types of cancer would occur. Mintz agreed to work with Jaenisch, who joined her lab as a visiting fellow for nine months. They showed that DNA from a virus, SV40, could be integrated into the DNA of developing mice and persist into adulthood without apparent tumor formation. Although only somatic cells were affected, meaning the DNA would not be passed on to future generations, these were the first mice ever made with foreign DNA and this experiment proved healthy genetically modified mammals could be created by viral infection. Using these techniques Mintz was able to establish the genetic basis of certain kinds of cancer and, in 1993, she produced the first mouse model of human malignant melanoma. Honors Mintz received numerous awards and honors including the first Genetics Society of America Medal (1981), and the first March of Dimes Prize in Developmental Biology shared with Ralph L. Brinster (1996). She was elected a fellow of the American Academy of Arts and Sciences (1982), American Association for the Advancement of Science (1973), the American Philosophical Society (1982), and won an honorary fellow of the American Gynecological and Obstetrical Society since 1980. She won the Papanicolaou Award for Scientific Achievement (1979), the Amory Prize (1988), the Ernst Jung Gold Medal for Medicine (1990), the John Scott Medal (1994), the American Cancer Society National Medal of Honor for Basic Research (1997), a citation for Outstanding Woman in Science (1993) from the New York Academy of Sciences, and,