Teenage Mutant Ninja Turtles: Cartoon vs Movie question?

In the cartoon, Splinter was a man who was cross contaminated with a rat and the ooze and became a giant rat. Hamato Yoshi was his friend and then became his enemy after some falling out (I think)...Yoshi became Shredder. But in the movie, Splinter was a rat, the pet of Yoshi, who was contaminated by the ooze at the same time as the turtles, and then mutated into a giant rat. Why the discrepancy between the cartoon and movie? What was the story in the comic books?