Question

RR (Red) Antirrhinum is crossed with white (WW) one. Offspring RW are pink. This is an example of

• A. dominant-recessive
• B. incomplete dominance
• C. hybrid
• D. supplementary genes.

Answer 1

The Correct Option is B

The given problem involves a cross between red and white Antirrhinum, with the resulting offspring being pink. Let's understand how this showcases the concept of incomplete dominance.

1. The genotypes involved in the question are:
   • RR: Red Antirrhinum
   • WW: White Antirrhinum
   • RW: Offspring showing pink flowers
2. Concept of Incomplete Dominance:
   • In incomplete dominance, one allele for a specific trait is not completely dominant over the other allele. This results in a third phenotype that is a blending of the traits of the parents.
   • In the case of Antirrhinum (snapdragons), crossing red (RR) with white (WW) results in pink (RW) offspring. This is a classic example of incomplete dominance.
3. Explanation for Other Options:
   • Dominant-recessive: If this were the mechanism, one color (either red or white) would completely mask the other. This is not observed in the given scenario.
   • Hybrid: Usually refers to the offspring resulting from the combination of different parents, but does not specify how traits are expressed.
   • Supplementary genes: Involves interaction of non-allelic genes affecting the expression of a trait, not applicable in this direct cross.

Therefore, the correct answer is that this is an example of incomplete dominance.