Question

A male rabbit of genotype AABBDDEE is crossed with a female rabbit of genotype aabbddee to produce ${F_1}$ hybrid offspring. How many genetically different gametes can be produced by this ${F_1}$ hybrid?
A. 4
B. 8
C. 16
D. 32

Answer 1

Any new progeny produced always resembles to its parents in morphological and physiological characteristics. When the parents genotypes are crossed, the first generation formed is known as the Filial 1 progeny, or commonly ${F_1}$ generation.

Complete answer:
Some of the traits are dominant over the others and are represented by capital letters while their recessive forms are represented by the small letters. If one of the parents has a genotype having all the dominant characters while the other has all the recessive characters (as given in this question), the ${F_1}$ progeny has dominant characters physiologically and a hybrid of both the traits in their genotype. Here, the male rabbit has a genotype of AABBDDEE that is dominant and the female rabbit has a genotype of aabbddee, which is recessive. Thus, when the dominant male rabbit is crossed with recessive female rabbit, the F1 generation will be having a hybrid genotype of AaBbDdEe (Law of Dominance).
When this ${F_1}$ hybrid is subjected to fertilisation, the gametes will be produced in such a way that each trait will have a chance to combine with any one of the next traits. ‘A’ could be combined to either ‘B’ or ‘b’. Similarly, both ‘B’ and ‘b’ could be combined with ‘D’ or ‘d’. In this way, 16 types of gametes could be produced.
The number of gametes produced can also be calculated by using the formula 2n, where n is the number of pairs of contrasting characteristics. So the number of gametes in this case will be 24=16. The four pairs of contrasting characteristics in this case are Aa, Bb, Cc, and Dd.

Thus, the correct option is (C) 16.

Note: In the four pairs of contrasting characters, segregation of each pair of the characters is independent of the other pairs of characters. These characters are combined in all the permutations and combinations. This law is known as “Law of Independent Assortment”.