13) Leber’s hereditary optic neuropathy, a form of young adult blindness, is linked to a small inherited mutation in mitochondrial DNA (mtDNA). Discuss some of the reasons why individuals with this disease may have differences in the severity and kinds of symptoms they display
Added by Adriana R.
Step 1
** Show more…
Show all steps
Your feedback will help us improve your experience
Adi S and 53 other Biology educators are ready to help you.
Ask a new question
Labs
Want to see this concept in action?
Explore this concept interactively to see how it behaves as you change inputs.
Key Concepts
Recommended Videos
Complete each sentence with the appropriate term. skeletal muscle tRNA genes varies from tissue to tissue is the same in all tissues transcribe electron transport chain homoplasmic translate different from the same as heteroplasmic brain Leber's hereditary optic neuropathy (LHON) results from mutations in mitochondrial genes. LHON symptoms are seen when optic nerve cells are homoplasmic for the disease mutation. Myoclonic epilepsy and ragged red fiber disease (MERRF) is caused by loss-of-function mutations in mitochondrial tRNA genes. People with MERRF are usually heteroplasmic because cells with only mutant mitochondria cannot translate mitochondrial mRNAs and die. The percentage of mutant mtDNAs in a mother's cells can be the percentage in her children's cells. Within one heteroplasmic person, the ratio of mutant to wild-type mtDNAs the same as. If the cells in a MERRF patient have 20% mutant mtDNAs, the tissue will not be affected. If the brain cells in a MERRF patient have 20% mutant mtDNAs, the tissue will be affected.
Adi S.
Leber's hereditary optic neuropathy (LHON) is a degenerative disease of the retina, caused by a mutation in a mitochondrial gene. If a woman and a man, both of whom who have LHON, mate what portion of their children do you expect to have LHON? If one of their daughters mates with a man who does not have LHON, what portion of her children do you expect to have LHON? If one of their sons mates with a woman who does not have LHON, what portion of his children do you expect to have LHON?
Kaela P.
In a study of a myopathy, several families exhibited vision problems, musde weakness, and deafness (M. Zeviani etal. 1990. American burnal of Human Genetics $47.904-914$ ). Analysis of the mtDNA from affected penons in these families revealed that large numbers of their mtDNA possessed deletions of varying length. Different members of the same family and even different mitochondria from the same person possessed deletions of different sizes; so the underlying defect appeared to be a tendency for the mitDNA of affected persons to have deletions. A pedigree of one of the families studied is shown here. The researchers conchided that this disorder is inherited as an autosomal dominant trait and they mapped the disease-causing gene to a position on chromosome 10 in the nucleus. a. What characteristics of the pedigree rule out inheritance of a trait encoded by a gene in the mtDNA? b. Explain how a mutation in a nuclear gene might lead to deletions in mtDNA.
Recommended Textbooks
Biology for AP Courses
Objective Biology for NEET
Introduction to General, Organic and Biochemistry
Transcript
18,000,000+
Students on Numerade
Trusted by students at 8,000+ universities
Watch the video solution with this free unlock.
EMAIL
PASSWORD