Fig. 4: Scheme of Release of Insects carrying a Dominant sterile Drive (RIDD) system.

a Drive inheritance of RIDD. In male drive heterozygotes, germline Cas9 activity converts wild-type alleles to drive alleles by homology-directed repair, while end-joining repair or incomplete homology-directed repair generates nonfunctional resistance (r2) alleles. Females carrying one drive allele are sterile. The most common type of r2 (~ 95%, marked by *) is also dominant sterile in females, though a small fraction are recessive sterile. A small fraction of wild-type alleles (< 1%) in the male germline may also remain uncut. b Concept of RIDD pest control strategy. Drive heterozygous males are continuously released into a wild population. Drive conversion and resistance allele formation take place in the male germline, so nearly all female progeny of drive males are sterile (drive carrier and most r2 carrier females are sterile). Over time, the frequency of drive carriers increases, and with a high enough release level, the population will eventually be suppressed.