Male and female dsxFCRISPRh heterozygotes (dsxFCRISPRh/+) that had inherited a maternal or paternal copy of the driving allele were crossed to wild type and assessed for inheritance bias of the construct (a) and reproductive phenotype (b). (a) Progeny from single crosses (n≥15) were screened for the fraction that inherited DsRed marker gene linked to the dsxFCRISPRh driving allele (e.g. G1♂→G2♀ represents a heterozygous female that received the drive allele from her father). Levels of homing were similarly high in males and females whether the allele had been inherited maternally or paternally. The dotted line indicates the expected Mendelian inheritance. Mean transmission rate (± s.e.m.) is shown. (b) Counts of hatched larvae for the individual crosses revealed a fertility cost in female dsxFCRISPRh heterozygotes that was stronger when the allele was inherited paternally. Mean progeny count (± s.e.m.) is shown. (***, p<0.001;****, p<0.0001; Kruskal-Wallis test).