animal DNA
http://www.lewrockwell.com/wallace/wallace178.html
about the dangers of losing our humanity, proposes the possibility that the replicants in Blade Runner may have had animal DNA integrated into them
quote: "The first example that comes to my mind is the movie Blade Runner, which was about artificial, genetically engineered humans called replicants. The movie, which is very subtle in many ways, suggests the replicants have animal DNA inserted into them. One is part turtle, one raccoon, one wolf, one snake, and one fish, probably shark."
I'm guessing Leon=turtle, Roy=wolf, Pris=racoon, Zhora=snake, ?=shark

