. A woman whose father was color blind (X-linked, recessive) and who has type A blood has accused a man who is himself color blind of fathering her child. The accused man has type B blood. For each of the following cases, indicate whether or not the man might be the father. Explain your answer by including the genotype of the child and demonstrating how that genotype could be produced.

Question

. A woman whose father was color blind (X-linked, recessive) and who has type A blood has accused a man who is himself color blind of fathering her child. The accused man has type B blood. For each of the following cases, indicate whether or not the man might be the father. Explain your answer by including the genotype of the child and demonstrating how that genotype could be produced. 
a) a color blind son with type O blood
b) a normal visioned son with type O blood
c) a normal visioned son with type AB blood
d) a color blind daughter with type B blood
e) a normal visioned daughter with type A blood

PsyDAG · Answer

a) Remember that the colorblind gene is sex-linked, on the X chromosome. Whenever the male has that chromosome, he is color blind.

b) Did the woman or her father have type A blood? If the woman and the accused father both had recessive O genes, it is possible.

c) this is also possible. Do a Punnett square with AO and BO blood types respectively.

d) Do Punnett square with colorblind gene and AO/BO.

e) Do Punnett square with colorblind gene and AO/BO.