U. researchers make major genetic discovery on mice

Three University Veterinary School researchers may have found the way to create a genetically perfect human. Or at least they can do it with mice. The three-member team, led by Professor of Reproductive Physiology Ralph Brinster, has developed techniques to transplant mice's immature sperm cells into the testis of an infertile mouse. These cells have been shown to grow and develop into normal mature sperm. "I believe that in the future, these techniques could be applied to any species, including people," Brinster told The Philadelphia Inquirer, adding that their implementation would most likely not be approved for human use in the near future. Further applications of this discovery include significant advances in permanently curing genetically transmitted diseases. Brinster said in a statement that the study proved that injected spermatogonial stem cells will continue to replicate for the entire lifetime of the mouse, developing into mature sperm. "These cells undergo self-renewal throughout life, and have the ability to transmit genes to successive generations," he said. "In this sense, they can be thought of as immortal." Brinster added that the variation in sperm development answers questions about normal and abnormal cell growth, giving insight into sources and remedies for serious diseases. The research, aided by University researchers James Zimmermann and Mary Avarbock, has demonstrated the capability to create improved farm animal species and to reverse certain types of infertility. But the new abilities also raise ethical questions of eugenics -- the creation of a superior human race by the development of "designer genes." "I'm not advocating [the use of these techniques in humans]," Brinster told the Inquirer. "There should be a lively debate about it. But if people should choose to use germ-line therapy, this is a method that might be considered in the long term." The study, which was published in yesterday's issue of Proceedings of National Academy of Sciences, has shown the rate of successful transplants ranged from 13 percent to 100 percent. The scientists are now working to determine ways to alter germ cells, making it possible to cure hereditary diseases such as muscular dystrophy, hemophilia, cystic fibrosis and sickle-cell anemia. In addition, the sperm of boys diagnosed with Hodgkin's lymphoma -- a curable disease that often leaves patients sterile after treatment -- may be removed and returned to them afterward, according to a statement by Georgetown University Medical Center representative Martin Dym. This may give the boys the ability to father children in the future, he added. Acting Dean of the School of Veterinary Medicine Alan Kelly said the study has excited University researchers. "I anticipate that these investigations will set new directions for research at the School of Veterinary Medicine," he said in a statement. "We are immensely proud of Dr. Brinster. His research is extremely exciting and has very important ramifications for veterinary medicine and animal agriculture."