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A student completed a genetics exercise by preparing the Punnett square drawn below - HSC - SSCE Biology - Question 5 - 2006 - Paper 1
Question 5
A student completed a genetics exercise by preparing the Punnett square drawn below. T represents a dominant allele and t represents a recessive allele. Parent 1 ga... show full transcript
Worked Solution & Example Answer:A student completed a genetics exercise by preparing the Punnett square drawn below - HSC - SSCE Biology - Question 5 - 2006 - Paper 1
Step 1
What were the likely genotypes of the parents?
Answer
To determine the likely genotypes of the parents from the provided Punnett square, we first analyze the gametes.
In the Punnett square, the gametes from Parent 1 are shown as TT and Tt, which indicates that Parent 1 contributed either a dominant allele (T) or a recessive allele (t). Given that TT can only come from a homozygous individual, we note that parent 1 must be homozygous dominant (TT).
Examining Parent 2, they contributed both the gametes Tt and tt. For Parent 2 to produce these combinations, they must be heterozygous (Tt), as they have both dominant and recessive alleles in their gametes.
Thus, the most accurate answer from the provided options is:
(C) Both parents were heterozygous.