Question

Part 1- Explain which traits would need to combine in order for a yellow cucumber and a green to make a green cucumber.

Answer 1

The color of this cucumber type is determined by two alleles:

- Y which is dominant and codes for the yellow color (dominant alleles are written in capital letters)

- y which is recessive and codes for green color (recessive alleles are written in lowercase letters)

Part 1 - a green cucumber will be obtained only when both alleles are recessive yy. This type is known as a homozygote and it is required that only the green trait is present.

- if the parents are as shown in the Punnett square (1 yellow heterozygote + 1 green homozygote), then half of the offspring will be green.

Side note - If the yellow parent, which has the dominant allele, were homozygote (YY), then none of the offspring would be green.

Part 2 - in order to obtain a yellow cucumber, it is required only the presence of a dominant yellow coding allele Y. Thus both heterozygotes (Yy) and homozygotes (Yy) will be yellow.

- if the parents are as shown in the Punnett square (1 yellow heterozygote + 1 green homozygote), then all the yellow offspring will be heterozygotes for yellow (Yy). 50% of the offspring will be yellow.

Side note - If the yellow parent, which has the dominant allele, were homozygote (YY), then all of the offspring would be yellow.

Answer 2

Part 1.

Answer:

Only the traits or allele for the green trait will be needed to make a green cucumber.

Explanation:

Here in the given example there are two allele responsible for the color of cucumber. One is Y which is dominant allele and codes for the yellow color.

While y is recessive allele and it will be code for the green color.

In case of heterozygous in which the genotype will be Yy but the phenotype will be always yellow because Y is dominant.

In case of genotype yy the phenotype will be green.

So for green cucumber there will be two y in the genotype.

Part 2.

Answer:

For yellow cucumber, there is need of only one dominant allele which codes for yellow.

Explanation:

According to the given punnet squre, There will be 4 genotypes from the breeding of a yellow cucumber and green cucumber.

The yellow cucumber is heterozygous or homozygous and its genotypes can be Yy and YY relatively.

But for green cucumber the genotype can only be homozygous which is yy.

In the punnet squre the 2 phenotype are yellow and green.

Hence for the yellow cucumber there is only need of one Y allele in genotype.