Mitochondrial Inheritance Flashcards
Describe the structure of mitochondrial DNA.
Closed circular molecules with each molecule containing a full set of mitochondrial genes.
How many mitochondria are there per human cell on average?
100
How are mitochondria inherited?
Maternally.
How many genes are in the human mitochondrial genome?
37 genes.
How many genes in the human mitochondrial genome are heavy strand (guanine-rich)?
28 genes.
How many genes in the human mitochondrial genome are light strand (cytosine-rich)?
9 genes.
Why is mitochondrial inheritance classed as ‘non-Mendelian’?
Mendelian inheritance presumes half the genetic material of a fertilised egg derives from each parent. This does not happen with the mitochondrial genome.
How can mitochondrial diseases be inherited?
Maternally or chromosomally.
If your mother has a mitochondrial mutation, what is the likelihood this mutation will be passed on?
100%
What happens to paternal mitochondria (from sperm) during fertilisation?
They are actively decomposed.
What are mitochondrial myopathies?
Neuromuscular diseases caused by mitochondrial damage.
What are the symptoms for mitochondrial myopathies?
Poor growth, muscle coordination loss, muscle weakness, visual/hearing/learning difficulties, heart/liver/kidney disease. Many others.
How does the HIV/AIDS treatment azidothyramidine (AZT) sometimes lead to abnormal mitochondrial function?
AZT inhibits DNA polymerase involved in HIV replication. Mitochondrial DNA polymerase gamma is also targeted as a result.
What is Leigh syndrome?
mtDNA disease. Symptoms include diarrhea, vomiting, seizures and trouble sucking/swallowing. Caused by loss of energy production. Leads to death in several years.
