Figure 5. Human DNA transfer in rat colon tumors by PCR-sequencing.

Representative pictures of PCR detection of a repetitive sequence of rat (LINE 1) in a rat tumor (DMH and DMH+SW480). (A) Alu Yd6 human sequences were only amplified from the colon tumors of DMH+SW480-treated rats. Rat tail and human cells were used as positive and negative controls. Human K-ras and RAB30 genes were only detected in the tumors of rats receiving DMH and SW480 cells. (B) Sequence analysis of the PCR product of RAB30 in a colon tumor treated with DMH+SW480 cells. Arrows indicate the position where the nucleotide sequence is different between species and clearly shows the existence of both sequences. Human SW480 cells (control).