Question

the punnett square shows a cross between two flowers that exhibit a complete dominance inheritance pattern for petal color. potential offspring are represented by flowers w, x, y and z. r is the allele for red petals, and r is the allele for blue petals. what percentage of the offspring would be expected to display the dominant phenotype? 25% 50% 75% 100%

Explanation:

Step1: Determine the genotypes of the parents

The male sex cells have alleles \( R \) and \( r \), and the female sex cells have alleles \( R \) and \( r \). So the parents' genotypes are \( Rr \) (male) and \( Rr \) (female).

Step2: Analyze the Punnett square

In a Punnett square for \( Rr\times Rr \):

• The possible genotypes are \( RR:Rr:Rr:rr \).
• According to the rule of complete dominance ( \( R \) is dominant for red petals), the phenotypes of \( RR \), \( Rr \), \( Rr \) (dominant) and \( rr \) (recessive).
• Count the number of dominant - phenotype offspring. There are 3 out of 4 offspring (\( W:RR \), \( X:Rr \), \( Y:Rr \)) that show the dominant phenotype (red petals).
• Calculate the percentage: \(\frac{3}{4}\times100\% = 75\%\)

Answer:

75%