STEP 7 Assess the effect of the environmental change on future generations. Mice with brown fur are still more likely to be eaten and are therefore no longer mating. Remove half of the genotypes (pairs of beans) that have the dominant brown fur phenotype. Hemate the resulting gene pool for another generation. Hecord the genotypes of this third generation in the chart below. Remember to use the correct alleles ( B and b ). (Note: You may not need all the rows in the chart.).