Dihybrid Cross Problems Dihybrid Problem 2: Fur Color and Tail Length in Mice In mice, black fur (B) is dominant overite fur (b), and long tails (L) are dominant over short tails (1). A heterozygous black, long-tailed mouse is crossed with a white. short-tailed mouse (BbLI x bbll). Guide Questions: 1. What are the genotypes of the parents? 2. Use the FOIL method to find the gametes. 3. What are the phenotypes and their ratios? 4. How many offspring will be black with short tails?