The transcription factor Pax6 is required continually during the life of a mouse (or a human) for the development and maintenance of the retina. Homozygous Pax6 knockout mice die soon after birth because Pax6 protein is also required in essential organs, such as the pancreas. a. In order to study the role of Pax6 in eye development, a researcher wants to generate a mouse that expresses Pax6 everywhere except in its eyes. Describe how you could construct such a mouse.