Figure 2.

Application of MS-RDA and MS-RDA-WEEC to a MeIQ-induced liver tumor. Amplicons (lanes 4 and 5; 2 μg/lane) were prepared from HpaII digests of DNA samples from an MeIQ-induced mouse liver tumor (lane 2; 5 μg) and a normal portion of the same liver (lane 3; 5 μg). Two cycles of competitive hybridization were performed using the amplicon from the tumor as tester and the amplicon from the normal portion as driver (series T–L; lanes 6 and 7; 1 μg/lane) and vice versa (series L–T; lanes 8 and 9). One and three bands were clearly visible after two cycles in series T–L and L–T, respectively (shown by open arrowheads). Three of the four products were high copy sequences, so the one (lane 10; 250 ng) and three clones (lane 11; 250 ng each) were added to respective driver DNA, and homologous fragments in the tester amplicon were eliminated in the course of competitive hybridization (MS-RDA-WEEC). After two cycles of competitive hybridization of both series (T–L, lanes 12 and 13; L–T, lanes 14 and 15), the bands corresponding to the first one and three MS-RDA products were clearly weakened, and other bands appeared. (A) Ethidium bromide staining. (B) The filter was hybridized with clone B10, obtained in series T–L WEEC. Gen., genomic; Am., amplicon; Cl, clone.