Mitochondrial genetics Flashcards
What is the structure of mitochondrial DNA?
Circular DNA molecule.
Two complimentary strands
Relatively small.
What are the 2 complimentary strands in mitochondrial DNA?
Heavy and light
What is the heavy strand in mitochondrial DNA rich in?
Guanine
What is the light strand in mitochondrial DNA rich in?
Cytosine
What genes does the mitochondrial DNA carry/
13 protein-coding genes
2 ribosomal RNA
22 translational RNA
The D loop
What is the D loop?
A non-coding region within the mitochondrial DNA.
What is the function of the D loop?
Regulation of replication and transcription.
What is mitochondrial DNA packaged into?
Nucleoids.
How many molecules of mitochondrial DNA is in a nucleoid?
3-7
Other than mtDNA what is in the nucleoids?
- DNA polymerase
- DNA binding proteins
- DNA helicase
- Transcription factors
- Chaperones
What are the genetic rules surrounding mtDNA?
- Polyploid Genome (more than one copy of mtDNA in each cell)
- Heteroplasmy
- Threshold effect
- Maternal inheritance
How many mitochondria does each cell contain?
Around 100.
What does polyploid mean?
There are multiple copies in each cell.
Why would mtDNA be important in ageing?
Really high mutation rate.
Why does mtDNA have a high rate of mutation?
Localised near the site of reactive oxygen species production.
A lack of protective histones
Limited repair mechanisms More frequent replication.
No introns (all mutations affect coding sequence).
