The release of genetically modified mosquitoes in the Florida Keys cleared a significant hurdle Friday when the U.S. Food and Drug Administration announced they pose no significant environmental danger. The preliminary findings, to be published in the Federal Register, will be open for public comment for the next 30 days. But the initial federal review likely clears the way for a long-delayed field trial by British producer Oxitec in the tiny affluent neighborhood of Key Haven a mile east of Key West. Pitched as a safer, more affordable way of battling Oxitec’s modified male mosquitoes are engineered to produce offspring...