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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.
Mitochondrial diseases range in severity from asymptomatic to fatal, and are most commonly due to inherited rather than acquired mutations of mitochondrial DNA. A given mitochondrial mutation can cause various diseases depending on the severity of the problem in the mitochondria and the tissue the affected mitochondria are in.
In general, mitochondrial DNA lacks introns, as is the case in the human mitochondrial genome; [144] however, introns have been observed in some eukaryotic mitochondrial DNA, [146] such as that of yeast [147] and protists, [148] including Dictyostelium discoideum. [149] Between protein-coding regions, tRNAs are present.
Mitochondrial DNA (mtDNA, the DNA located in mitochondria, different from the DNA in the nucleus of a cell) and Y-chromosome DNA are commonly used to trace ancestry in this manner. mtDNA is generally passed un-mixed from mothers to children of both sexes, along the maternal line, or matrilineally.
The hypothetical woman at the root of all these groups (meaning just the mitochondrial DNA haplogroups) is the matrilineal most recent common ancestor (MRCA) for all currently living humans. She is commonly called Mitochondrial Eve. The rate at which mitochondrial DNA mutates is known as the mitochondrial molecular clock. It is an area of ...
Mitochondrial matrix has a pH of about 7.8, which is higher than the pH of the intermembrane space of the mitochondria, which is around 7.0–7.4. [5] Mitochondrial DNA was discovered by Nash and Margit in 1963. One to many double stranded mainly circular DNA is present in mitochondrial matrix. Mitochondrial DNA is 1% of total DNA of a cell.
In human mitochondrial genetics, L is the mitochondrial DNA macro-haplogroup that is at the root of the anatomically modern human (Homo sapiens) mtDNA phylogenetic tree. As such, it represents the most ancestral mitochondrial lineage of all currently living modern humans, also dubbed "Mitochondrial Eve". Its two sub-clades are L1-6 and L0.
Schematic tree of haplogroup L0. MSA: Middle Stone Age, LSA: Later Stone Age, ka: thousand years ago. This phylogenetic tree of haplogroup L0 subclades is based on the paper by Mannis van Oven and Manfred Kayser Updated comprehensive phylogenetic tree of global human mitochondrial DNA variation [3] and subsequent published research.