Question

The seed color of the garden pea was used to derive Mendel's two laws: segregation and independent assortment. Now, we know that the Y allele codes for the enzyme converting green to yellow chlorophyll. The mutant allele, y, is caused by a loss-of-function mutation on this gene. Let's assume that this mutation manifests its phenotype through the haploinsufficiency mode. Answer the following questions.

P YY (Yellow) x yy (Green)
F1 Yy (?) x Yy (?)
F2 1YY (?) : 2Yy (?): 1yy (?)
1. Which color would be recognized as a dominant trait, and what would be ratio of F2 between Yellow and Green seeds? (You need to explain why)
2. In this situation, which breeding scheme should be the proper testcross and what will be the outcome of this testcross? (You also need to explain why)

Answer 1

Answer:1.Yellow color will be dominant and the ratio is Yellow to green allele is 3:1

2.A recessive test cross should be appropriate.The result will be all yellow colored pea plants.

Step-by-step explanation:

Since Yy x Yy produces

1YY,2Yy and 1yy then it shows that YY and Yy are 3 yellow pea plants and 1yy green pea plant.

A recessive test cross should be used because a recessive genotype being homozygous can be noticed by its physical appearance