Question

Incomplete dominance is found in
A. Pisum sativum
B. Antirrhinum majus
C. Both A and B
D. None of the above

Answer 1

Hint: Incomplete dominance is a condition where the presence in the genotype of an organism of dominant genes does not entirely mask the effects marked due to the presence of a recessive allele. The progeny is intermediate of both the parents.

Complete answer: Incomplete dominance is a kind of intermediate inheritance where one gene is not fully expressed over its paired gene for a specific phenotype. This results in a third phenotype in which a mixture of the dominant and recessive phenotypes is the expressed physical feature. In simpler words, incomplete dominance is a sort of intermediate inheritance in which one allele is not fully dominant over the other allele for a particular trait. This results in a third phenotype in which a mixture of the dominant and recessive phenotypes is the articulated physical feature. Related to however distinct from codominance, is incomplete hereditary dominance. An additional phenotype is formed in codominance, but both alleles are fully expressed. In AB blood type inheritance, co-dominance is exemplified. Example: Incomplete dominance is seen between red and white snapdragon plants in cross-pollination experiments. In the recessive allele that produces the white colour (r), the allele that produces the red colour (R) is not fully expressed. The resulting descendants are pink. (RR) Red, (rr) White and (Rr) Pink are the genotypes. Mirabilis jalapa and Antirrhinum majus are other common examples of this form of dominance.
So, option B- Antirrhinum majus is the correct answer.

Note: There are two distinct phenomena of codominance and incomplete dominance. Codominance is a special type of dominance in which the genes uniformly influence the trait. Incomplete dominance is only seen in heterozygous genes where both dominant and recessive genes are present.