Besides re-engineering the mosquito, scientists are tinkering with dozens of insects, fueled by the discovery of so-called "jumping genes" that can slice into DNA's double helix and insert a "cassette" of foreign genetic material. The newest jumping genes, called "transposons" in the lab, are capable of moving genes between different insect species. Here's a quick glance at some of the leading transgenic projects:
Medfly: The king of California's agricultural pests. New wrinkle: U.S. Department of Agriculture scientists are attempting to express a sperm-killing gene in the medfly's testes. Other research involves introducing a gene that will make the pests less able to withstand cold.

