Mitochondrial DNA is DNA found in mitochondria within a eukaryotic cell. Mitochondria are tiny organelles that are often referred to as the energy powerhouses of cells and contain their own genome with a modified genetic code. Just like nuclear DNA, mitochondrial DNA replicate, transcribe, and translate independently in its own organelle. The human mitochondrial DNA (mtDNA) is a double-stranded, circular molecule the molecule contains tightly compacted 37 genes coding for two Ribosomal RNAs (rRNAs), 22 transfer RNA (tRNAs) and 13 polypeptides. The mtDNA-encoded polypeptides are all thirteen protein subunits of four biochemical complexes of the oxidative phosphorylation system. In compared with other sites in human genome, Mitochondrial DNA (mtDNA) has a high mutation rate.
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It is not unusual for siblings to share identical mtDNA found in their mother. This is largely believed to be because of the dilution of paternal contribution the egg contains an average of 200,000 mtDNA molecules whereas the sperm only contains an average of five molecules. There are occasional cases, that it could be inherited paternally. This is a recent finding, it is rare for it to happen, but not impossible since the tail structure of a sperm, has mtDNA
It is not unusual for siblings to share identical mtDNA found in their mother. This is largely believed to be because of the dilution of paternal contribution the egg contains an average of 200,000 mtDNA molecules whereas the sperm only contains an average of five molecules. There are occasional cases, that it could be inherited paternally. This is a recent finding, it is rare for it to happen, but not impossible since the tail structure of a sperm, has mtDNA