Question

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? \boxed{\quad}:\boxed{\quad} what percent of the offspring will be heterozygous? \boxed{\quad}\\%

Explanation:

Step1: Determine Genotypes

Heterozygous (Aa) × Homozygous recessive (aa). Gametes: Aa gives A, a; aa gives a, a.

Step2: Complete Punnett Square

• Cell 1: A (from Aa) × a (from aa) = Aa (heterozygous)
• Cell 2: a (from Aa) × a (from aa) = aa (homozygous recessive)
• Cell 3: A (from Aa) × a (from aa) = Aa (heterozygous)
• Cell 4: a (from Aa) × a (from aa) = aa (homozygous recessive)

So genotypes: Aa, aa, Aa, aa. Total offspring = 4. Homozygous (aa) = 2. Heterozygous (Aa) = 2.

Step3: Calculate Ratios/Percentages

• Ratio (homozygous : total): \( \frac{2}{4} = \frac{1}{2} \), so 1:2.
• Percent heterozygous: \( \frac{2}{4} \times 100 = 50\% \).

Answer:

Ratio: 1:2
Percent: 50%