Fig. 3: A marked chromosome split gene drive in Culex quinquefasciatus.

a Graphical representation of the experimental design, which allows to track donor and receiver chromosomes. b Genetic cross scheme used to test homing efficiencies using a marked chromosome approach. Precursor crosses: w4- homozygous males were crossed with cd-,vasa-Cas9 homozygous females to generate w4-/w4+; cd-,vasa-Cas9/cd+ trans-heterozygote offspring, which was then intercrossed to isolate G0 w4-/w4-;DsRed+ males carrying at least one copy of the cd-,vasa-Cas9 allele. These G0 males were then mated to white-gRNA6-eGFP females. From their female progeny we isolated G1 test animals carrying both DsRed+ and eGFP+ fluorescent markers, which would have the w4+,white-gRNA6/w4-,w6+; cd-,vasa-Cas9/cd+ genotype. The test G1 females were then crossed in a pool with w4-/w4- males. The females were allowed to lay eggs, at which point single rafts were collected, and hatched separately to perform a phenotypical analysis of each independent germline. Potential homing events are indicated by blue triangles in the cross scheme. Below the genetic cross is a Punnett square representation of the expected genotypes with the white-gRNA-eGFP transgene labeled in either dark cyan (original) or light cyan (copy). c Graph reporting the inheritance rates observed for the transgenes in the G2 progeny derived from G1 females. d Homing efficiency rate calculated using the receiver chromosomes only, in the marked-chromosome strategy. Estimated means and 95% confidence intervals were calculated by a generalized linear mixed model, with a binomial (‘logit’ link) error distribution, and are presented above the graphs for each data set. Raw phenotypic scoring is provided in Supplementary Data 3.