Having freckles (F) is dominant over not having freckles (f). A parent with freckles is crossed with a parent without freckles. The Punnett square shows the possible genotypes of the offspring.

Question

What is the probability that an offspring will have a homozygous dominant genotype?
0
%

What is the probability that an offspring will have a heterozygous genotype?
%

What is the probability that an offspring will have a homozygous recessive genotype?
%

Answer 1

To determine the probabilities of the offspring's genotypes, let's first establish the genotypes of the parent organisms involved in the cross.

• The parent with freckles can have either a homozygous dominant genotype (FF) or a heterozygous genotype (Ff).
• The parent without freckles must have a homozygous recessive genotype (ff).

Assuming the parent with freckles is heterozygous (Ff), we can set up the Punnett square as follows:

              F             f
       ----------------------
    f |      Ff          ff
       |
    f |      Ff          ff

From this Punnett square, we can determine the probabilities of the different genotypes:

1. Homozygous dominant (FF): In this scenario, there are 0 offspring with the homozygous dominant genotype since there is no FF combination in the Punnett square.

   • Probability: 0%

2. Heterozygous (Ff): There are 2 Ff offspring out of a total of 4 (2 Ff and 2 ff).

   • Probability: \(\frac{2}{4} \times 100 = 50%\)

3. Homozygous recessive (ff): There are 2 ff offspring out of a total of 4.

   • Probability: \(\frac{2}{4} \times 100 = 50%\)

In summary:

• Probability of homozygous dominant genotype (FF): 0%
• Probability of heterozygous genotype (Ff): 50%
• Probability of homozygous recessive genotype (ff): 50%