In a typical Mendelian genetics lab, students cross flies or other organisms of known genotypes, score phenotypes of the offspring, and determine if their results are significantly different from expected phenotype ratios. For this unit, the traditional dihybrid cross lab has been reformatted into an inquiry-based exercise. Students receive two vials of wild-type (Canton S or Oregon R) flies and two vials of mutant flies, but they are not told the genotype of assigned mutants. During the first week they must identify the mutation(s) present by comparing the adults in the two vials. Subsequently students must cross mutant flies to wild-type flies and, based on phenotype ratios in the F1 and F2 generations, determine the pattern of inheritance and most likely genotype of the original mutants. Students decide for themselves what crosses must be done to uncover the pattern of inheritance. This free selection includes the Table of Contents, Preface, and Index. As a special bonus, the chapter entitled A Brief Introduction to Inquiry is also included.