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.
10. Based on Tables 1 and 2, what fraction of the offspring of Cross 3 had 1 or more copies of the E allele of Gene E？
Your Answer is
Correct Answer is H
Explanation
It can be seen from table 1 that both black coat and brown coat have at least one E allele, corresponding to cross 3 in table 2, and the ratio of E allele should be (2+2)/(2+2+2 ) = 4/6 = 2/3