I\'m stuck on this last problem and could really use someone\'s help. 10. Caleb
ID: 64317 • Letter: I
Question
I'm stuck on this last problem and could really use someone's help.
10. Caleb has a double row of eyelashes that he inherited from his mother. His maternal grandfather is the only other family member with this trait. Veronica, a woman with normal eyelashes, falls madly in love with Caleb and they marry. Their first child, Polly, has normal eyelashes. Veronica is pregnant again and desperately hoping this child will inherit the double eyelashes. What are the odds that this child will have the double eyelashes? Draw the pedigree for this family. What is the pattern of inheritance? Explain your answer (2 points).
Explanation / Answer
Double eyelashes are caused by a disorder known as distichiasis. It is a condition in which hair, or eyelashes, may grow from the openings of tiny oil-producing glands in the lids. These glands are called the meibomian glands.
This is an autosomal dominant inheritance.
This type of disorder needs only one defective allele to produce the phenotype. That's why the maternal grandfather has inherited to his mother and to Caleb.
Caleb marries a normal woman veronica and their first child Polly has normal eyelashes. So there is 50% chance of their next child to have this disorder.