Passage II

Each dog in a particular population has a black brown, or yellow coat. In this population, coat color is determined by 2 unlinked genes: Gene B and Gene E. Gene B has 2 alleles: B and b. Gene E also has 2 alleles: E and e. Table 1 shows the possible genotypes for Gene B and Gene E and the resulting coat color phenotypes.

Two of the dogs with black coats were crossed 3 times (Crosses 1-3). The coat colors of the offspring produced in each cross are shown in Table 2.

11. Consider the offspring of each of the 3 crosses. Based on Tables 1 and 2, some of the offspring of which of the crosses, if any, could have had only recessive alleles of Gene B and Gene E ?

Answer and Explanation

Your Answer is

Correct Answer is B

Explanation

In the question stem, it is mentioned that some offsprings only have recessive alleles of Gene B and Gene E, so that means that the genotype of these offsprings is bbee. According to table 1, this genotype corresponds to yellow coat, and crosses in table 2 Both 2 & 3 have yellow coat