Question

a. What do the letters R and I represent ? b. What is the genotype of the pink-flowered snapdragons? c. Explain whether the alleles show dominance, incomplete dominance, or codominance. d. If red-flowered snapdragons and ivory-flowered snapdragons are crossed, what percentage of their offspring would be expected to be pink-flowered?

Answer 1

Answer:

a) R= allele for red colored flower

I= Allele for ivory flowers

b) Genotype of pink flowered plant: RI

c) Incomplete dominance

d) 100%

Explanation:

When the dominant allele is not able to fully mask the expression of the recessive allele in the heterozygous state, it is said to be incomplete dominance. The R and I alleles impart red and ivory color respectively to the flowers of the snapdragon plant. The heterozygous genotype "RI" imparts a pink color to the flowers and therefore, the alleles are said to exhibit incomplete dominance.

The genotype of red-flowered snapdragon plant = RR. The genotype of ivory flowered snapdragon plant= II. When a red-flowered snapdragon plant is crossed with an ivory flowered snapdragon plant, the progeny is heterozygous in nature with the "RI" genotype. The phenotype of the progeny is "Pink flower" since the R allele is incompletely dominant over the allele I.