Question

practicing monohybrid crosses

white feathers in canaries are dominant to yellow feathers. a heterozygous canary is crossed with a homozygous recessive canary.

what is the ratio of the offspring that are homozygous to the total number of offspring?

what percent of the offspring will be heterozygous?

Explanation:

Define alleles and parental genotypes

Using the Monohybrid Cross knowledge point

• Let \(W\) represent the dominant allele for white feathers.
• Let \(w\) represent the recessive allele for yellow feathers.
• Heterozygous parent genotype: \(Ww\).
• Homozygous recessive parent genotype: \(ww\).

Set up the Punnett square

Using the Punnett Square knowledge point

• Parent 1 (\(Ww\)) alleles: \(W\) and \(w\).
• Parent 2 (\(ww\)) alleles: \(w\) and \(w\).
• Offspring genotypes:
• Box 1: \(Ww\) (heterozygous)
• Box 2: \(ww\) (homozygous recessive)
• Box 3: \(Ww\) (heterozygous)
• Box 4: \(ww\) (homozygous recessive)

Calculate homozygous ratio

Using the Monohybrid Cross knowledge point

• Homozygous offspring: 2 (\(ww\)) out of 4 total.
• Ratio of homozygous to total: \(2:4\), which simplifies to \(1:2\).

Calculate heterozygous percentage

Using the Monohybrid Cross knowledge point

• Heterozygous offspring: 2 (\(Ww\)) out of 4 total.
• Proportion: \(\frac{2}{4} = 0.5\).
• Percentage: \(50\%\).

Answer:

Question 1

What is the ratio of the offspring that are homozygous to the total number of offspring?
\(1:2\) (or \(2:4\))

Question 2

What percent of the offspring will be heterozygous?
\(50\%\)