3.12 GEN - Genetics of Mitochondrial Diseases. Flashcards
What is the endosymbiotic theory saying about mitochondria?
Mitochondira can be modeled as a prokaryote trapped inside a eukaryotic cell.
Cells eating cells.
How many mitochondria are there in any given cell?
Various amounts depending on the type and location of the cell.
What is the role of mitochondria in our bodies?
Convert carbon sources to ATP and CO2, using O2.
What type of cells are mitochondria similar to? What type of cellular genome do they have? What type of cellular DNA replication machinery do they contain?
Similar to prokaryotes.
Prokaryotic genome.
Viral DNA replication machinery.
What is the structure integrity of the outer mitochondrial membrane (continuous solid gate, fenestrated pourous)? How about the inner membrane?
Outer membrane = colander, contains holes, filters things in and out.
Inner membrane = tight seal, not letting stuff move easily.
Regarding mitochondrial genome structure, is it stable or unstable, how does this affect the mutation rate in mitchondria?
Nucleoid.
Very very stable.
Minimal amounts of mutations => not many mutational changes through time. Your mitochondria is very similar to your mom’s.
If your fathers had gotten a bad sunburn on his balls the day before he impregnated your mom with you, and there was considerable damage to the sperm that were posted in his vas deferens. What affect would this have on your mitochondria?
A) None at all.
B) You may have adapted mitochondrial mutations from his sperm.
C) You weren’t born because you died in the uterus do to lack of functional mitochondria.
A) None at all. You get your mitochondria from your mother ya big fool!!
Define stochastic?
The outcome is randomly determined based on the theory of probability.
Random but predictable due to probability.
What is the concept behind heteroplasmy, what causes this?
Heteroplasmy = there will be different mitochondria (with different genomic material) inside the same cell.
Mitochondria do not have control over their DNA segregation, so when they undergo cell division you can get different combinations of mitochondrial DNA in each mitochondria. This may lead to a aggregation of mutated DNA, good DNA, or a mix.
If a pt. comes in 2yo with mitochondrial related disease, is this congenital or is it due to de novo mutations? why?
Congenital.
Too young to have acquired a bunch of de novo mutations and passed them on during replication and resulted in a disease state.
True or False? A mutation in one mitochondrial DNA in a cell will cause a disease state? Explain answer.
False.
“Not a on/off switch, its a volume control. Too much noise = disease state.”
Compare mtDNA vs. chromosomes. (Structure, replication, introns + exons, number of copies of genes, histones, coding + non-coding regions).
mtDNA:
Circular.
Replicate like prokaryotes, use viral polymerase.
Solid genes, no introns (junk).
2 copies of genes, one from mom one from dad.
No histones, cannot use histones as target in therapy.
Almost no non-coding regions.
If you isolated a mitochondria out of a cell would it still have the same function as if it were in the cell, why or why not?
No, mitochondria sheds genetic information into the nucleus of the cell, therefore some genes necessary for mitochondrial functioning are located in that nucleus.
Do mitochondria chromosomes undergo recombination, why why not? How can this be helpful in clinical genetics?
No, there are no different mitochondria in the cell to undergo recombination with.
Used a lot to detect family lineages due to this lack of recombination and the preservation of mitochondria.
Genomes of mitochondria act as haplotypes. What the hell does that mean?
Genomes of mitochondria act as clusters inherited as a group.
Will all be inherited together usually, spontaneous mutations MAY occur.
