Shown below is the pedigree of a rare neurodegenerative diseasein humans.
a. Based on the pedigree,characterize each of the following modes of inheritance as likely,unlikely, or impossible: autosomal dominant, autosomal recessive, Ylinked, X-linked dominant, and X-linked recessive. Justify yourreasoning.
Further scrutiny of members of this family reveals thefollowing: 1) The diseaseâs degree of expression varies amongindividuals, with some mildly affected, others moderately affectedand still others severely affected; and 2) Individual III-14 waspreviously married. Her ex-husband is phenotypically normal, withno history of the disease in his family going back tengenerations. He has custody of the coupleâs two children, a girland a boy, both of whom are affected with the disease. The partialpedigree is shown below (the âslashâ represents separation ordivorce)
b. Do these findingseliminate any of the remaining âlikely or unlikelyâ modes ofinheritance listed in part (a)? Are any of thesemodes of inheritance still possible? If so, which one(s) andwhy?
c. Is mitochondrialinheritance a likely, unlikely or an impossible mode of inheritancefor this disease? Does it provide an explanation for the diseaseâsvariable expressivity?
d. How can mitochondrialinheritance explain individual III-14?
Shown below is the pedigree of a rare neurodegenerative diseasein humans.
a. Based on the pedigree,characterize each of the following modes of inheritance as likely,unlikely, or impossible: autosomal dominant, autosomal recessive, Ylinked, X-linked dominant, and X-linked recessive. Justify yourreasoning.
Further scrutiny of members of this family reveals thefollowing: 1) The diseaseâs degree of expression varies amongindividuals, with some mildly affected, others moderately affectedand still others severely affected; and 2) Individual III-14 waspreviously married. Her ex-husband is phenotypically normal, withno history of the disease in his family going back tengenerations. He has custody of the coupleâs two children, a girland a boy, both of whom are affected with the disease. The partialpedigree is shown below (the âslashâ represents separation ordivorce)
b. Do these findingseliminate any of the remaining âlikely or unlikelyâ modes ofinheritance listed in part (a)? Are any of thesemodes of inheritance still possible? If so, which one(s) andwhy?
c. Is mitochondrialinheritance a likely, unlikely or an impossible mode of inheritancefor this disease? Does it provide an explanation for the diseaseâsvariable expressivity?
d. How can mitochondrialinheritance explain individual III-14?
