[IB Biology SL at GHS: Genetics Reviews]
15. In the fairy tale country of Rexatopia, it is a royal decree that only women of royal blood (1st or 2nd cousins) can marry a prince or king. For that reason, the royal persons or Rexatopia have become inbred and many royals thus have or carry the recessive bleeding disease known as Hemophilia.

Using the chart at right, determine the expected phenotype ratio of the offspring for King Billy and Queen Alicia.

a) 100% normal blood clotting.

b) 50% normal blood clotting : 50% hemophilia

c) 25% normal daughters : 25% daughters with hemophilia : 25% normal sons : 25% sons with hemophilia. (In this case, the phenotype ratio must include both the sex and whether they are "normal" or have the disease.)

d) 100% normal daughters : 25% normal sons : 25% sons with hemophilia.

 

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Slichter