Question

A botanist has acquired a group of pea plants. All of the pea plants have yellow pea pods (the recessive form of this trait) except for one, which has green pea pods (the dominant form of this trait). The botanist decides to use a test cross to determine the genotype of the green pea pod plant for this trait. The botanist performed the test cross and found the following: 50% of the offspring had yellow pea pods and 50% of the offspring had green pea pods. Based on this information, what was the genotype of the initial green pea pod plant

Answer 1

Answer:

Hetezygous

Explanation:

The genotype of the initial green pod plant would be heterozygous.

Let pea pod color be represented by C (c) alleles.

First, let us assume that the genotype of the green pea pod plant is homozygous dominant, CC. This was crossed with homozygous recessive, cc.

           CC   x   cc

      Cc   Cc   Cc   Cc

All the progeny will have Cc genotype with phenotypically green color. This is in contrast to the result obtained from the test cross in the illustration, hence the genotype of the initial green pea pod plant cannot be homozygous dominant.

Now, let us assume that the genotype is Heterozygous, Cc.

       Cc   x   cc

 Cc   Cc   cc   cc

50% of the progeny has Cc genotype with phenotypically green color while the remaining 50% has cc genotype with phenotypically yellow color. This is consistent with the result from the illustration.

Hence, the genotype of the initial green pea pod plant is heterozygous.