Answer:
An example of circular double-stranded DNA molecules is the mitochondrial genomes that are 16,569 bp long and are present as one or more copies within all mitochondria of a cell. Thus mitochondrial DNA (mtDNA) is present in hundreds to thousands of copies per cell.
mtDNA is maternally inherited, so siblings will share the same DNA as their mother but not that of the father.
mtDNA is present in cells at a high copy number.
mtDNA is typically sequenced in the two hypervariable regions.
Explanation:
mtDNA is useful primarily for identity testing. mtDNA analysis may become essential when only a distant relative is available for a reference specimen.
In database searches of autosomal STR data from unidentified human remains or missing person relatives, the algorithms for the search often produce several potential matches, and mitochondrial DNA analysis is needed to identify the true match.
Deficiency wise, pathological alterations of mtDNA may occure and, it fall into three major classes: point mutations, deletion-duplications and disordered mtDNA content, that is, copy number.
On how to overcome these deficiency, the maintenance and integrity of the mitochondrial genome depend on several poorly understood factors.
Theoretically, defects in any of the proteins involved in mtDNA replication might affect mtDNA copy number. MtDNA replication is also highly dependent on mitochondrial dNTPs supply, and mutations in several genes involved in mitochondrial dNTP synthesis may therefore cause MDS (Mitochondrial DNA depletion syndrome).
