Question
Hitchhiker's thumb (H) is dominant to no hitchhiker's thumb (h)A woman who does not have hitchhiker's thumb marries a man who is heterozygous for hitchhiker's thumb . What is the probable genotypic ratio of the of their children? 3:1Hh:hh 2:2Hh:hh 0:4 Hh:hh 4:0 Hh:hh
Answer
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Horace
Professional · Tutor for 6 years
Answer
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Explanation
## Step1: Identify parental genotypes### The woman has the genotype `hh` (recessive) because she does not have a hitchhiker's thumb. The man is heterozygous `Hh` (dominant allele `H` and recessive allele `h`).## Step2: Set up Punnett square### To determine the genotypes of their children, use a Punnett square with the man's genotype `Hh` across the top and the woman's genotype `hh` along the side.## Step3: Complete the Punnett square### Fill in the Punnett square by combining the alleles from each parent. The possible combinations are `Hh` and `hh`.### | | H | h |### |-----|-----|-----|### | h | Hh | h |### | h | Hh | h |## Step4: Determine ratios### Count the genotype frequencies. There are two `Hh` and two `hh`, resulting in a ratio of `2:2` for `Hh` to `hh`.