We want to study linkage between the gene determining red hair and the gene for freckles, so we find families that include a parent who is heterozygous for both traits and a parent who is homozygous recessive for both traits. We make sure that each heterozygous parent resulted from a union between grandparent with red hair and freckles and a grandparent with brown hair and no freckles. The resulting offspring genotypes are shown in table below.
1) What are the genotypes of the gametes that created the heterozygous parent?
2) Did crossing over occur? Explain your reasoning.
3) Calculate the recombination frequency of the two genes.
4) Calculate the distance between the genes in centimorgans (cM).
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Table
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# Offspring
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Genotype
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110
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RrFf
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400
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Rrff
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380
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rrFf
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110
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rrff
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