Hemophilia is a recessive sex-linked trait in humans.  Sickle-cell anemia is a recessive trait on an autosome.  A couple are both carriers of the sickle-cell trait.  The man and woman are normal, but the woman is a carrier for hemophilia.   How many of their male children would you expect to have both sickle-cell anemia and hemophilia?  How many of their female children would have both conditions?

In humans, albinism (lack of skin pigment) is an autosomal recessive trait. The first child of two normally pigmented parents is an albino. Which of the following is true about this family? SELECT ALL THAT ARE CORRECT. A) Their first child (described above) has a homozygous recessive genotype B) The next child born to this couple has a 25% chance of being albino. C) If the next child born to this couple is male, he has a greater chance of being albino. D) The parents are both heterozygous for albinism. E) The probability of their second child being albino is 0% F) If the second and third child born to this couple are albino, the fourth child has 100% chance of also being albino.

A woman with normal blood clotting mates with a man who has hemophilia. Their first child is a boy who has hemophilia. Tests show that the father and son both have the same form of hemophilia, that it is X-linked recessive, and that the boy has normal genetic inheritance. You can predict that if the couple produces more children together, then the odds are that: Select one: O a. All of the children will have hemophilia. b. Half of the boys and half of the girls will have hemophilia. O C. None of the rest of the children should have hemophilia. O d. Half of the boys and none of the girls will have hemophilia.

Adenike and her partner, Debare, are expecting their first child. Adenike is healthy as are her two sisters but her brother has PKU, a recessive disorder of the PAH gene. Genotypically he must be pah-/pah-. Neither of Adenike's parents has PKU but both of her grandmothers did. Debare is a carrier of Sickle Cell trait, which means he has one allele for wildtype hemoglobin (HbA) and one allele for Sickle Cell (HbS), making him HgA/HbS. More importantly, he has two alleles for Marfan Syndrome, a pleiotropic dominant disorder that can affect up to 30 different traits (M+/M+). No one in Debare's family has ever had PKU and no one in Adenike’s family has ever had Sickle Cell or Marfan Syndrome. They consult a genetics counselor over concern of the health of their baby. The genetics counselor collects the medical histories of three generations; their grandparents, their parents, and them. In her calculations, she produces a phenotypic key that indicates M = Marfan, Hb = sickle cell, and pah-…

Hypophosphatemia (vitamin D-resistant rickets) is inherited as a sex-linked dominant trait (H). A) A normal woman and a man with hypophosphatemia marry. What is the chance of having daughters with rickets? Sons? B) A heterozygous woman and a normal man marry. Does the mother have rickets? What is the chance of having daughters with rickets? Sons?

In humans, blue eyes are inherited as a recessive autosomal trait and color blindness is an X-linked recessive trait.  A woman with blue eyes and normal color vision (her father was colorblind) marries a man who has normal color vision.  The man has brown eyes, but his mother had blue eyes.  What is the probability that this couple will have a child with normal vision and blue eyes?

A couple finds out that both the male and the female are heterozygotes (carriers) for Tay Sachs. Draw a punnet square for this couple. What is the likelihood that this couple will have an offspring with Tay Sachs?