Scientists working in a different field and in a different organism (mice) first discovered the function of the Pitx1 gene. To determine what the Pitx1gene did, these scientists intentionally mutated the Pitx1protein-coding region in mice so that the Pitx1 protein was no longer produced. These mice died before birth and had miniaturized hind limbs. a. What do you think these scientists concluded about the function of the Pitx1 protein after carrying out this experiment?

b. How is the genetic change that occurred in stickleback fish with reduced pelvises in freshwater lakes different from the one that scientists produced in the mice?

c. Why do you think stickleback fish with a Pitx1mutation are able to survive but not the mice?