Figure 6. Human DNA transfer in rat colon tumors by FISH.

Representative photographs FISH analyses of rat repetitive sequences (LINE 1) and human (Alu Yd6) in a colon tumor from a rat treated with DMH+SW480 cells (A). Pictures at left (blue) are nuclei stained with DAPI, green are rat specific LINE 1 signals. Red are human Alu Yd6 signals and orange are cells showing both signals. B. Representative photographs of a colon tumor from a rat treated with DMH only. Absent red signals represent the lack of human sequences in these cells. Co-incubation with both probes at the right confirms the lack of DNA transfer.