Question

1. (2 pts) Attached ear lobes (f) are inherited as an autosomal recessive trait. The dominant allele, F, produces free hanging ear lobes. Sam and Beth both have free earlobes, but their first child has attached earlobes. a. What are the likely genotypes of Sam and Beth with respect to the ear lobe locus? Sam: F Beth: FF b. With respect to the earlobe locus, Sam's genotype is homozygous,/(heterozygous or hemizygous? (Circle the correct answer). c. If Sam and Beth have another child, what is the probability that this child will have attached earlobes? 2. (4 pts) Achondroplasia is a short-limbed dwarfism that is inherited as an autosomal dominant disease. The mutant allele that causes this form of dwarfism (D) is dominant to the normal allele at this location (d) Individuals who inherit 2 alleles for dwarfism (DD) typically have a very severe form of achondroplasia that causes extreme shortening of the bones and an underdeveloped rib cage. These individuals are usually miscarried or stillborn. Tom and Vonna both have achondroplasia (but each of them has 1 average-sized parent). Tom and Vonna have 3 children, 2 of whom have achondroplasia. Tom and Vonna also had 2 stillborn children a. What are the likely genotypes of Tom and Vonna with respect to the achondroplasia locus? b. If Tom and Vonna have another child, what is the probability that this child will be of normal stature (NOT have achondroplasia)? c. If Tom and Vonna have 3 more children, what is the probability that all 3 of them will have achondroplasi (be heterozygous at this locus)? d. Consider the 2 children who were stillborn. What do you think the genotypes of these children were w respect to achondroplasia? Why?

Answer 1