Fused spermatids and spermatids with altered number of mitochondria in cnt1FD were calculated and compared with those of control flies w1118 and cnt1FD;cnt1::GFP. We show that cnt1FD mutants have an average of two defective spermatids per cyst compared with the controls (Supplementary Figure S7D). This evidence concerns the gene SLC28A1 and cyst.