Hemophilia is an X-linked recessive disorder that results in an individual not having a functional gene for a clotting factor and therefore unable to clot blood. A couple has 4 boys. One of the boys has just been diagnosed with hemophilia. What is the probability that all of the other 3 boys will also have hemophilia?

Mary has hemophilia, an X-linked recessive trait. From which of the following individuals could Mary NOT have inherited a hemophilia allele? O Her father O Her father's mother O Her mother's mother O Her father's father O Her mother's father

A couple is going to have a baby. They are concerned about sickle cell anemia, which results from having the homozygous recessive combination of the sickle cell gene ("s"), which produces abnormal hemoglobin. Having at least one normal version of the gene ("S") results in normal hemoglobin. The woman is heterozygous, and so is the man. What alleles does mom have? What alleles does dad have?

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-…

Using the given pedigree chart, suppose individuals III-1 and III-2 are expecting their sixth child. What is the chance (percent) that the sixth child will have the sickle cell trait? 

One form of the bleeding disorder known as von Willebrand disease is an autosomal recessive disease. A man who is a carrier marries a woman who is also a carrier of the disease. (a) What percentage of their children are likely to have a disease phenotype? (b) What percentage of their children are likely to have a normal phenotype? (c) What percentage of their children are likely to be carriers of the disease?

Sickle cell anemia is caused by an individual carrying two recessive copies of the hemoglobin gene (hemoglobin gene is labeled Hb, and the recessive version is Hbs). Thus, to have sickle cell anemia, a person must have the genotype HbSHbS. A person that is HbAHbA carries two copies of the normal hemoglobin gene and does not have sickle cell anemia. A person that is heterozygous (HbAHbS) produces enough normal hemoglobin to not have sickle cell anemia but is also resistant to malaria. People that are heterozygous are called “carriers” because they carry the recessive allele but do not express the recessive phenotype. a. A couple are both resistant to malaria but do not have sickle cell anemia. Draw a Punnett square to represent this cross. b. What is the probability that the couple has three children where one child does not have a recessive allele, one child is resistant to malaria and does not have sickle cell anemia, and one child has sickle cell anemia?

Baldness is a recessive, X-linked trait. Mom has a full head of hair but she is a carrier for baldness and her husband has a full head of hair. What are the chances of they having a child who is bald? 0% (no chance)   50%   75%   100% (all of them will be)   25%

A boy with cystic fibrosis (a recessive disorder) is born to a couple who appear to be normal. What are the chance (percent or ratio) that any other children born to this couple will also have cystic fibrosis?

Boe is normal and his wife is not color-blind, she is a carrier. Which of the following children they can't have? all of them carrier daughter normal daughter color-blind son color-blind daughter