Genetic engineering's fishy results.

Public debate over genetically modified organisms (GMOs) has largely focused around their benefits and drawbacks to human beings (see "Food Fight," cover story, July/August 2003), but a recent study conducted at Purdue University is likely to lead the discussion in a different direction: environmental safety. Male Japanese medaka fish, genetically modified to grow 83 percent larger than normal, were introduced into a mixed population of unmodified medakas. Though the modified medakas mated more frequently, their offspring were less viable. In a laboratory setting, only 70 of the GMO offspring reached reproductive age for every 100 of the unmodified offspring, meaning that only fractions of the breeding population survive. "As the population becomes more and more genetically modified, there are fewer normal males that modified males compete with, resulting in a smaller and smaller population as time goes on, ultimately leading to population extinction," says Richard Howard, a Purdue researcher. The results of this study are the first hard evidence for the "Trojan Gene" theory, which" predicts that a genetic modification, touted as beneficial, may have unseen repercussions. CONTACT: Purdue University News Service, (765)4942096, http://news.uns.purdue.edu.