Jane has blue eyes and Keith has brown eyes - Edexcel - GCSE Biology - Question 2 - 2013 - Paper 1
Question 2
Jane has blue eyes and Keith has brown eyes.
They have a daughter Sue who has blue eyes.
The allele for brown eyes is dominant over the allele for blue eyes.
(a) ... show full transcript
Worked Solution & Example Answer:Jane has blue eyes and Keith has brown eyes - Edexcel - GCSE Biology - Question 2 - 2013 - Paper 1
Step 1
Complete the sentence by putting a cross (X) in the box next to your answer.
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Answer
Sue has the genotype Bb.
Since she has blue eyes, which is a recessive trait, and her father has a genotype of Bb, she must inherit one blue allele from one of her parents and a brown allele from Keith.
Step 2
State the genetic term used to describe an individual with two different alleles for the same gene.
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Answer
The genetic term used to describe an individual with two different alleles for the same gene is heterozygous.
Step 3
Complete the Punnett square for Jane and Keith.
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Answer
The Punnett square for Jane (bb) and Keith (Bb) is as follows:
B | b
----------------
b | Bb | bb
----------------
b | Bb | bb
In this square, 'Bb' indicates children with brown eyes (heterozygous), and 'bb' indicates children with blue eyes (homozygous recessive).
