Give the genotypes of the ABO blood groups for individuals 1 and 2.

Do not include the genotypes for the Rhesus blood groups in your answer.

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Explain one piece of evidence from Figure 3 that the allele for Rhesus positive is dominant.

Calculate the probability of individuals 1 and 2 producing a Rhesus positive son with blood group A (individual 3). You can assume that individual 1 is heterozygous for the Rhesus blood group.

Show your working.

Scientists determined the frequencies of the ABO alleles and ABO phenotypes in a large population. They then used a statistical test to determine if the frequencies of the four phenotypes differed significantly from the frequencies expected according to the Hardy–Weinberg equation.

The frequencies of the IA and IO alleles were 0.15 and 0.65. What is the frequency of the IB allele?

Name the statistical test you should use to determine if the observed frequencies of the four phenotypes differed significantly from the frequencies expected according to the Hardy–Weinberg equation.

State how many degrees of freedom should apply.

The scientists concluded that the observed frequencies of the four phenotypes differed significantly from the expected frequencies. Use your knowledge of the Hardy–Weinberg principle to suggest two reasons why.

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