How many different types of gametes are possible to be formed by an individual if its genotype for a particular trait is AABbccDd?
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 4
A gamete gets one allele of each gene. A homozygous pair (AA, cc) can give only one kind of allele, while a heterozygous pair (Bb, Dd) gives two kinds. So the number of gamete types is 2n, where n is the number of heterozygous pairs.
AA gives A only; Bb gives B or b; cc gives c only; Dd gives D or d.
Heterozygous pairs: Bb and Dd, so n = 2.
Gamete types = 22 = 4: ABcD, ABcd, AbcD, Abcd.
Option (2) 8 — Incorrect. 8 = 23 would need three heterozygous pairs; this genotype has only two.
Option (3) 16 — Incorrect. 16 = 24 would need all four pairs heterozygous (AaBbCcDd).
Option (4) 32 — Incorrect. 32 = 25 would need five heterozygous pairs, more genes than the genotype has.