Mitochondrial Genetics Flashcards
Mitochondrion
Cell organelle
Site of respiration
Production of ATP (energy)
SNP
Single Nucleotide Polymorphism
Allele
An alternate form to a gene
Heteroplasmy
cells contain a mixture of organelle genomes
Cells can either be homoplasmic wild type or homoplasmic mutant
Homoplasmic
Cells contain only one type of organelle genome
Genetic Bottleneck
Reduction in population size leaving little genetic variation
Maternal Inheritance
Transmission of genes located in the mitochondria
Mitochondria is only passed on from one generation to the next via the mother
Mitochondria in cells
A cell typically has thousands of mitochondria
each cell contains between 10-100 compartments which each house 0-11 copies of the mitochondrial genome
The Genomes of Mitochondria
Located within highly condensed structures (nucleoids) - The number of nucleoids present in mitochondria depends on the growth and the energy demands of the cell.
MtDNA replication occurs independently of the cell cycle. (RANDOM occurrence of replication) some mtDNA replicate lots, some not many times at all
Mitochondria Replication
- Mitochondrial c/some in nucleoid
- Mitochondrial genome replicates
- Mitochondrion begins to divide via BINARY FISION
- BINARY FISSION is complete. (two separate mitochondrion’s
Binary Fission
Division in Half
Asexual reproduction into two identical daughter cells
Circular vs Linear DNA
Most species have circular DNA but some species have linear DNA . e.g. green algo , yeast and ciliated protozoan
mtDNA of protozoan parasites
Protozoan parasites have single mitochondrion (kinetoplast) with a large network of minicircles and maxicircles
Mitochondrial Genome
Very compact in humans.
- Adjacent genes overlap eachother slightly
- Virtually no intergenic regions
- No introns
- No protective histones
S. cereisiae is 4 x larger than in humans. it has introns and has long intergenic regions
