Mosquitoes are been imbued with a gene that makes them unable to transmit a strain of lethal malaria that kills over 1 million people every year. This gene has been spliced into mosquitoes and is quite successful. Though one problem still remains, how to give these mosquitoes a leg up in the population so that the gene spreads. Apparently normal natural selection is not enough and so a gene found in Tribolium castaneum has shown that when a female carriers a particular element of a gene all her offspring will to. Those that don't will simply die. As a result of this the element Medea spreads very quickly through the population. The mechanism by which this works is still being studied but shows great promise. If this sought of gene can be applied to the new mosquitoes it would mean that the inability to transmit malaria would spread very quickly through the population. this would result in close to 1 million people a year not dieing from said disease.
http://www.sciencemag.org/cgi/content/full/316/5824/597
-Josh Gilchrist
