Fig. 4: Evaluation of transgenesis efficiency in Drosophila melanogaster using gRNA scaffold variant.

a Constructs designed for Drosophila transgenesis experiments. Both constructs contain the w5-gRNA driven by the Drosophila U6:3 promoter and are marked with GFP fluorescence to identify positive transformants. Two homology arms flank the gRNA element to facilitate HDR-mediated transgene integration into the Drosophila genome. The two constructs differ only in their gRNA scaffold for the presence of either the “Loop” modification or the control, “Original” construct. b Both constructs were injected separately into a Dm-vasa > Cas9 line to ensure Cas9 expression in the germline. c Germline transformation rates were calculated by dividing the number of G0 independent single-pair crosses giving transformants (GFP+) by the total number of G0 crosses performed. A one-tail randomization test for a difference in proportions was performed to determine whether the “Loop” scaffold variant caused an increase in transgenesis when compared to the “Original” gRNA (p value = 0.039).