CHEF gel and Southern hybridization analysis of transconjugants obtained from filter mating experiments employing wild-type E99 as the donor and OG1RF as the recipient. (A) I-ceuI-restricted DNA from donor E99 (lane 1); three transconjugants, IG9, IIB3, and IIE7 (lanes 2, 3, and 4, respectively); and recipient strain OG1RF (lane 5). (B and C) Also shown are Southern hybridization analyses of I-ceuI-restricted DNA from donor strain E99 (lane 1), the transconjugants (lanes 2 to 4), and recipient strain OG1RF (lane 5) using a 23S rRNA gene probe (B) and a bee locus-specific probe (C). Bacteriophage lambda concatemers were used as molecular size markers (lane M; New England Biolabs, Beverly, MA).