Rapgap1 mRNA localization is dependent on posterior group genes. Rapgap1 RNA detected by in situ hybridization. Embryos collected from females of the following genotypes: (A) wild-type, (B) oskarAK (four copies oskar), (C) oskar-bcd-3′UTR, (D) vasaD1, (E) tudorWC8, and (F) nanosBN. Anterior is to the left.