Fluorescence in situ hybridization of mitotic chromosomes. Mitotic chromosomes were hybridized with a Wolbachia-specific WRi_004290 probe amplified from sequence-verified plasmids and visualized at 60X. While hybridization was not detected in polytene chromosomes with WRi_004290, it is detected in the mitotic chromosomes. The fluorescence appears to be localized to the centromere of the abnormally large fourth chromosomes of D. ananassae. The larger 2nd and 3rd chromosomes are visualized nearby as well as a likely X chromosome. Hybridization to the fourth chromosome is consistent with the LGT being largely heterochromatic.