Question

the allele for curly hair is incompletely dominant. if a mother is homozygous for curly hair and the father is homozygous for straight hair, what percentage of the offspring will exhibit characteristics of both parents?
25 percent
50 percent
75 percent
100 percent

Explanation:

Step1: Define Genotypes

Let’s denote the allele for curly hair as \( C \) (homozygous curly: \( CC \)) and straight hair as \( S \) (homozygous straight: \( SS \)). Incomplete dominance means heterozygotes (\( CS \)) show a blend of both traits (e.g., wavy hair, exhibiting both curly and straight characteristics).

Step2: Perform Punnett Square

The mother (\( CC \)) can only pass \( C \) alleles, and the father (\( SS \)) can only pass \( S \) alleles. The Punnett square for \( CC \times SS \) will have all offspring with genotype \( CS \).

Step3: Determine Percentage

Since all offspring (\( 100\% \)) are \( CS \) (heterozygous, showing a blend of both parents’ traits in incomplete dominance), the percentage of offspring exhibiting both parents’ characteristics is \( 100\% \).

Answer:

100 percent