The genotypes of 2 guinea pigs, for 2 traits are represented as AABB and aabb. The guinea pigs are mated and the offspring eventually mate with eachother. Of the second generation, what genotypes would be phenotypically different from the originals?

To work through the question, we need to remember that there are 2 traits or characteristics we are looking at for the guinea pigs - A/a and B/b. We need to work out the different ways the alleles can pair for each characteristic separately. When mating first happens between the original pair, there is only one possible genotype for the first generation offspring for the 2 characteristics. A pairs with a and B pairs with b giving the offspring as AaBb. This can be shown easily in a punnet square.For the second generation, we then repeat the process of working out the allele pairs for each characteristic using the first generation genotype of AaBb. Again, this is easiest to work out using separate punnet squares for each trait.For trait 1 (I.e A/a):AA, Aa, Aa and aa are the possible allele pairs.For trait 2 (I.e. B/b):BB, Bb, Bb and bb are the possible allele pairs.We can then work out the different genotypes of the second generation offspring by combining each pair of alleles of the 2 traits in a final punnet square. The final genotypes will therefore be:AABB, AaBB, aaBB, AABb, AaBb, aaBb, AAbb, Aabb, aabb.If A and B are dominant alleles, the genotypes that would show a different phenotype to the original pair would be aaBB, aaBb, AAbb and Aabb.