Im just so damn confused!

How do white rats get on the market then. If all high whites get MC, how is there even any to make more? you get what im sayin? My girlfriend has my camera charger or i would have shown you pics by now. But she has a blonde mask with a stripe that goes all down her back, and little blonde spots on her butt. I just dont want these pups that were born on Sat 9 to be suffering.