Consider a cross where some off springs in a generation have genotype ppqqrr. Which of these CAN be a genotype of either parent?

Options

A. PPQQRR
B. PPQRr
C. PpQqRr
D. PpQQRr

Answer

To determine which genotypes can be from the parents of the offspring with the genotype ppqqrr, we need to analyze the inheritance of alleles.

### Step-by-Step Solution:

1. **Understanding the Offspring Genotype**:
- The offspring has the genotype ppqqrr, which means it is homozygous recessive for all three traits (p, q, and r).
- This indicates that both alleles for each gene are recessive.

2. **Determining Parental Genotypes**:
- For an offspring to be pp (homozygous recessive), each parent must contribute at least one recessive allele (p). Therefore, at least one parent must have the genotype that includes the recessive allele (either homozygous recessive pp or heterozygous Pp).
- The same logic applies to the other two traits (q and r).

3. **Possible Genotypes of Parents**:
- **Parent 1**: Could be homozygous recessive (pp) or heterozygous (Pp).
- **Parent 2**: Could also be homozygous recessive (qq, rr) or heterozygous (Qq, Rr).
- Thus, the possible combinations for the parents could be:
- One parent homozygous recessive for all traits (ppqqrr).
- One parent homozygous recessive and the other heterozygous for one or more traits (e.g., Ppqqrr, ppQqrr, etc.).

4. **Conclusion**:
- The most appropriate answer is that at least one parent must be heterozygous for the traits involved (e.g., Pp, Qq, Rr) to produce the recessive offspring (ppqqrr).
- Therefore, the genotype of either parent can be heterozygous for any of the traits.