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Mitochondrial genetic mutations that occur in the nuclear DNA can occur in any of the chromosomes (depending on the species). Mutations inherited through the chromosomes can be autosomal dominant or recessive and can also be sex-linked dominant or recessive.
The human mitochondrial molecular clock is the rate at which mutations have been accumulating in the mitochondrial genome of hominids during the course of human evolution. The archeological record of human activity from early periods in human prehistory is relatively limited and its interpretation has been controversial.
This means that mitochondrial DNA disorders may occur spontaneously and relatively often. Defects in enzymes that control mitochondrial DNA replication (all of which are encoded for by genes in the nuclear DNA) may also cause mitochondrial DNA mutations. Most mitochondrial function and biogenesis is controlled by nuclear DNA. Human ...
Microheteroplasmy is the presence of mutations levels of up to about 2−5% of mitochondrial genomes. In human mitochondrial DNA, microheteroplasmy constitutes hundreds of independent mutations in one organism, with each mutation usually found in 1–2% of all mitochondrial genomes.
Mitochondrial DNA is the small circular chromosome found inside mitochondria. These organelles, found in all eukaryotic cells, are the powerhouse of the cell. [1] The mitochondria, and thus mitochondrial DNA, are passed exclusively from mother to offspring through the egg cell.
Homoplasmy is a term used in genetics to describe a eukaryotic cell whose copies of mitochondrial DNA are all identical. [1] In normal and healthy tissues, all cells are homoplasmic. [2] Homoplasmic mitochondrial DNA copies may be normal or mutated; [1] however, most mutations are heteroplasmic [2] [3] (only occurring in some copies of ...
Haplogroup J is a human mitochondrial DNA (mtDNA) haplogroup. The clade derives from the haplogroup JT, which also gave rise to haplogroup T. Within the field of medical genetics, certain polymorphisms specific to haplogroup J have been associated with Leber's hereditary optic neuropathy. [2]
A nonstop mutation, also called a stop-loss variant, is a point mutation that occurs within a stop codon. Nonstop mutations cause the continued translation of an mRNA strand into what should be an untranslated region. Most polypeptides resulting from a gene with a nonstop mutation lose their function due to their extreme length