Monkey Knockout
In an early step toward developing a potentially invaluable animal model, scientists, for the first time, have genetically modified a nonhuman primate (A.W. Chan et al., "Transgenic monkeys produced by retroviral gene transfer into mature oocytes," Science, 291:309-12, Jan. 12, 2001). Researchers at the Oregon Regional Primate Research Center at the Oregon Health Sciences University in Portland used a replication-incompetent retrovirus as a vector to deliver the gene for green fluorescent protein (GFP) into a rhesus monkey oocyte (a mature egg). According to lead author Anthony W.S. Chan, the procedure, in the works for two and a half years, is a tricky one. Oocytes are hard to come by, and relatively little is known about primate embryology. Of the 224 eggs fertilized, half of them developed; forty embryos were selected and placed into 20 surrogate monkey moms. Of the five successful pregnancies, there were three live...