22. Mary is not bald. Mary's mother and Mary's husband, John, are bald. John has a non-bald father. Mary is pregnant with a boy/girl dizygotic twin. What is the probability that the twins would develop male pattern baldness in adult life?
A. The boy: 100%; the girl: 25%
B. The boy: 50%; the girl: zero
C. 50% for both
D. The boy: 75%; the girl: 25%
E. The boy: 100%; the girl: 50%
F. The boy: 50%; the girl: 25%
25. Mark and Sue both are affected with autosomal recessive blindness, and have 2 normal children. Which of the followings best represent the genotype of this couple, and what is the cause of this event?
A. Mark is AAbb, and Sue is AAbb ......de novo mutation
B. Mark is aabb, and Sue is aaBB ...... locus heterogeneity
C. Mark is aaBB, and Sue is aaBB .......allelic heterogeneity
D. Mark is aabb, and Sue is Aabb .....variable expressivity
E. Mark is aaBB, and Sue is AAbb........locus heterogeneity
22. Mary is not bald. Mary's mother and Mary's husband, John, are bald. John has a non-bald father. Mary is pregnant with a boy/girl dizygotic twin. What is the probability that the twins would develop male pattern baldness in adult life?
| A. | The boy: 100%; the girl: 25% | |
| B. | The boy: 50%; the girl: zero | |
| C. | 50% for both | |
| D. | The boy: 75%; the girl: 25% | |
| E. | The boy: 100%; the girl: 50% | |
| F. | The boy: 50%; the girl: 25% |
25. Mark and Sue both are affected with autosomal recessive blindness, and have 2 normal children. Which of the followings best represent the genotype of this couple, and what is the cause of this event?
| A. | Mark is AAbb, and Sue is AAbb ......de novo mutation | |
| B. | Mark is aabb, and Sue is aaBB ...... locus heterogeneity | |
| C. | Mark is aaBB, and Sue is aaBB .......allelic heterogeneity | |
| D. | Mark is aabb, and Sue is Aabb .....variable expressivity | |
| E. | Mark is aaBB, and Sue is AAbb........locus heterogeneity |
