On the horizon

Modified maize is not on the move

When scientists found genetically modified maize sprouting in Mexico five years ago, they worried that seeds of the wayward crop would spread, threatening the genetic diversity of local varieties.

Now, a team of US and Mexican researchers is sounding the "all clear" - at least for 125 fields in 18 locations in the state of Oaxaca in southern Mexico. The team concludes that if unwelcome maize is present, it's extremely rare. Any errant imports likely withered under the region's harsh growing conditions.

The team sifted through 153,746 maize seeds in 2003 and 2004 looking for two "designer" genes common to genetically modified maize sold in the United States. They came up empty-handed. Even so, the researchers say, the study provides a firmer basis for assessing the potential environmental and health effects of genetically modified crops in the region studied. The results appear in this week's Proceedings of the National Academy of Sciences.

"Planetary" systems come in all sizes. Just ask University of California at Berkeley astronomer Franck Marchis. He and colleagues from France have discovered the first triple-asteroid combo in our solar system: two small asteroids orbiting around a larger one in the main asteroid belt between Mars and Jupiter.

The larger chunk of space rock, dubbed 87 Sylvia, was discovered in 1866 and named for the mother of Romulus and Remus, the mythical founders of Rome. In 2001, astronomers found that Sylvia sported one moon roughly 11 miles across and orbiting 843 miles away. This latest moon is about 4 miles across and orbits "mom" at a distance of 440 miles. The astronomers dubbed the "twins" Romulus and Remus, of course. Details of the discovery are in Thursday's edition of Nature.