Board Thread:Questions and Answers/@comment-65.130.222.229-20130209231901/@comment-74.134.201.163-20130316235548

In the 2003 series and original comics, yes, the mutagen just turns animals into animal-human hybrids. In the 2012 series, their DNA is combined with the last thing they touched. For the turtles, it's splinter. For splinter, it was an alleyway rat. Yeah, the turtles and Miwa (possibly Karai) are totally half siblings.