Question

Construct a pedigree using the following information about the expression of curly hair in three generations of a family. Be sure to include all possible information. (4 marks) - The proband’s grandmother had straight-hair and his grandfather had straight hair

- His grandparents had four children. The oldest and youngest were both females with straight hair. The third child was the only one with curly hair.

- The youngest was his mother. His father had straight hair as well. -He is the oldest of his parents’ children. His brother is the second oldest and his sister is the youngest. Of the three of them, only his brother has curly hair.

-His uncle with curly hair married a woman with straight hair. Their daughter has curly hair.

b) Using the information from this pedigree, and assuming that the trait is inherited through a single gene with two alleles, is this a recessive or dominant trait? Explain. (1.5 marks)

c) Can you determine if this trait is autosomal or X-linked? Explain your answer. (2 marks)

d) Provide the genotypes of the third generation for both autosomal and X-linked inheritance. If there is more than one possible genotype, include both. (1.5 marks)

e) If the proband were to have children with a woman with curly hair, what is the likelihood of them having a curly-haired daughter? What about a curly-haired son? Answer this question for both autosomal and X-linked inheritance. (1.5 marks

Answer 1