A number of researchers are working on developing gene drives to engineer organisms such as mosquitos to eradicate diseases like malaria or Zika virus that they carry. However, the Economist reports that organisms may be able to develop resistance to such drives.
Sometimes, the Economist notes, gene drives aren't properly inserted into the target region and the DNA repair mechanism fixes the gap, but could alter it so that the guide RNA from a CRISPR-based gene drive no longer recognizes the region. It's become resistant.
Researchers led by Phillip Messer at Cornell University conducted a series of experiments in which they applied a CRISPR-based gene drive to a population of mosquitos. As they report in PLOS Genetics this week, they found that the constructs they generated led to resistance at a high rate — between 60 percent and 4 percent of flies became resistant, depending on their genetic background.
But the Economist notes that there are a few tricks to try to work around this resistance. For instance, it says that multiple guide RNA could be included so the drive can cut at multiple spots or the drive can be targeted to the middle of a gene needed for survival. That way, if the drive isn't properly inserted, the organism dies.