Question

Interpret the Punnett square showing two pea plants with yellow peas producing offspring with green peas (yy).

a) Dominant trait expression
b) Recessive trait expression
c) Co-dominant trait expression
d) Incomplete dominance trait expression

Answer 1

Two pea plants with yellow peas that produce a green pea offspring demonstrate recessive trait expression in genetics. The Punnett square predicts that the offspring are homozygous recessive (yy) for the green pea trait, which shows when both parents are heterozygous (Yy).

Step-by-step explanation:

When interpreting a Punnett square for the scenario where two pea plants with yellow peas produce offspring with green peas (yy), we are looking at recessive trait expression. In pea plants, yellow peas (Y) are dominant to green peas (y). This indicates that both parents must be heterozygous (Yy) to produce a green pea offspring (yy). In the F1 generation, the cross of a true-breeding yellow pea plant (YY) with a green pea plant (yy) would result in all yellow peas because the yellow trait is dominant. However, when these yellow heterozygous plants (Yy) are crossed with each other in the F2 generation, the Punnett square can predict the occurrence of the recessive green peas (yy). The offspring's genotype would be a combination of the parental alleles and the phenotypical appearance would be determined by these genetic combinations. Only the homozygous recessive genotype (yy) will show green peas, which is a clear example of recessive trait expression.