Reference no: EM133920631

Once Mr. M's initial diagnosis was determined, he called home to share the news. Initiating this discussion prompted Mr. M's mother to share some key aspects of his family history. Mr. M's father was the youngest of 5 children, and he ha two older sisters and two older brothers. Mr. M's mother is one of 6 children, and she had four older brothers and one younger sister. Both Mr. M's mother and father are of African American descent, and the extended family has not generally traveled to locations that might challenge underlying genetic conditions. Interestingly, Mr. M's father had a daughter with another women prior to starting a family with Mr. M's mother. This young women, Mr. M's half -sister, has a family of her own with her African American husband. Notably, her son has sickle cell anemia and received extensive blood transfusions through age 4. He is now 14 years old and his condition is relatively well-managed. Her younger daughter appears healthy. (As part of his work-up, Mr. M's blood had been examined by isoelectric focusing (IEF), a specialized form of electrophoresis, and this analysis showed presence of both HbA and HbS forms of his hemoglobin B chain. (HbAS)

Questions

Draw a pedigree showing the family history described. On the pedigree, indicate, which, if any, individuals are obligate heterozygotes.

What is the probability of Mr. M's niece being a heterozygote? What is the probability of his half-sister conceiving another affected child?