Year 12 maths · D.1 · Genetics
Punnett square percentages
Draw the 2 × 2 square: each box is 25%.
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In a cross Aa × aa, "a" is a recessive allele. What percentage of the offspring are expected to show the recessive trait (aa)?
Answer: 50%
In a cross Aa × Aa, "a" is a recessive allele. What percentage of the offspring are expected to show the recessive trait (aa)?
Answer: 25%
In a cross aa × aa, "a" is a recessive allele. What percentage of the offspring are expected to show the recessive trait (aa)?
Answer: 100%
Tip: Draw the 2 × 2 square: each box is 25%.
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