Question

If a plant that has round seeds has a parent that has wrinkled seeds, what is its genotype? (Assume that round is dominant.)​

Answer 1

Again, this is determined by the alleles a plant has at just one genetic locus. In this case, the allele for wrinkled seeds (W) is dominant to the allele for round seeds (w). This means that plants with both genotypes WW and Ww have wrinkled seeds, and only those with genotype ww have round seeds.

Answer 2

The genotype of the progeny plant is Rr.

Mendel's laws of inheritence

• Mendel studied inheritance in pea plants and discovered that genes(genotype) impart phenotypical characteristics to organisms.
• He stated that each gene has two alleles. The recessive trait will only be expressed if both the alleles are recessive.
• Let us assume 'r' is the recessive allele and 'R' is the dominant allele for the shape of pea seeds.
• If both the parent gametes have dominant R, the progeny will have round seeds(RR).
• However, in this case, since one of the parents has wrinkled seeds(recessive trait), it delivers a recessive allele to the progeny(r).
• Therefore, in order for the progeny to have round seeds, the other parent needs to give the dominant allele(R) to the progeny.

        R(from one parent) + r(from parent with wrinkled seed = progeny(Rr)

• Thus, the genotype of the progeny with round seeds will be Rr.