The creation of a functional chimeric fetus via nuclear transfer between two different species has been demonstrated for the first time, with significant implications for wildlife conservation (Cloning 2, 79–90, 2000). Previous in vitro studies had shown the feasibility of nuclear transfer between sheep, pigs, monkeys, or rats and enucleated bovine oocytes. In the new report, a collaboration of academic and industrial researchers has taken the first steps in cloning an endangered wild Asian ox (or gaur; Bos gaurus) by electrofusing fibroblasts from the animal's skin with enucleated bovine oocytes. Twelve percent of the reconstructed oocytes developed into blastocysts, and 18% of these developed to the fetal stage when transferred to pseudopregnant cows. Inspection of fetuses removed at days 46 and 54 (twins), and a fetus aborted at day 202, revealed no evidence of gross external abnormalities. Microsatellite and cytogenetic analysis also confirmed that the genome of the cloned animals was gaurus in origin, whereas the mitochondrial DNA was bovine. According to lead author Robert Lanza of Advanced Cell Technology (Worcester, MA), one pregnancy is still ongoing and is due for delivery by cesarean in late November. “We are also working with the Spanish government to use this technology in goats to clone an extinct bucardo mountain goat from preserved cells,” he says.