Nuclear mitochondrial DNA segment

Nuclear mitochondrial DNA (NUMT) segments or genetic loci describe a transposition of any type of cytoplasmic mitochondrial DNA into the nuclear genome of <a href="/facts/Eukaryotic/SkwyPLMA">eukaryotic</a> organisms.
More NUMT sequences of different sizes and lengths in the diverse number of eukaryotes have been detected as <a href="/facts/Whole_genome_sequencing/WNuHaU2K">whole genome sequencing</a> of different <a href="/facts/Organisms/j8JkL09u">organisms</a> accumulates. They have often been unintentionally discovered by researchers who were looking for <a href="/facts/Mitochondrial_DNA/goC0ex0X">mitochondrial DNA</a> (mtDNA). NUMTs have been reported in all studied eukaryotes, and nearly all mitochondrial genome regions can be integrated into the nuclear genome. However, NUMTs differ in number and size across different species. Such differences may be accounted for by interspecific variation in such factors as <a href="/facts/Germline/QI4bKK8Q">germline</a> stability and mitochondria number. After the release of the mtDNA into the <a href="/facts/Cytoplasm/Wa0sE6xf">cytoplasm</a>, due to the mitochondrial alteration and <a href="/facts/Morphology_(biology)/Nl3B0myy">morphological</a> changes, it is transferred into the nucleus and inserted by double-stranded break repair processes into the <a href="/facts/Nuclear_DNA/5wzCJQlb">nuclear DNA</a> (nDNA). A correlation has been found between the fraction of noncoding DNA and NUMT abundance in the genome, and NUMTs are observed to have non-random distribution and a higher likelihood of being inserted in certain genomic regions. Depending on the location of the insertion, NUMTs might disrupt gene function. In addition, de novo integration of NUMT pseudogenes into the nuclear genome can have adverse effects.
In the <a href="/facts/Cat/82d0y6D5">domestic cat</a>, mitochondrial gene number and content were amplified 38 to 76 times in the cat's nuclear genome besides being transposed from the cytoplasm. Cat NUMT sequences did not appear to be functional due to the discovery of multiple mutations, differences in mitochondrial and nuclear genetic codes, and the apparent insertion within typically inert <a href="/facts/Centromere/AWxF1ClY">centromere</a> regions. The presence of NUMT fragments in the genome is not problematic in all species; for instance, it is shown that sequences of mitochondrial origin promote nuclear DNA replication in <a href="/facts/Saccharomyces_cerevisiae/sX9MGFrz">Saccharomyces cerevisiae</a>. Although the extended translocation of mtDNA fragments and their co-amplification with free mitochondrial DNA has been problematic in the diagnosis of mitochondrial disorders, in the study of population genetics and <a href="/facts/Phylogenetic_analyses/bw4rsovt">phylogenetic analyses</a>, scientists have used NUMTs as genetic markers to determine the relative rate of nuclear and mitochondrial mutation and recreating the evolutionary tree.
In 2022, scientists reported the discovery of ongoing <a href="/facts/Mitochondrial_DNA/goC0ex0X">transfer of mitochondrial DNA into DNA in the cell nucleus</a>. Previously, NUMTs were thought to have arisen before the existence of humans. 66,000 <a href="/facts/Whole_genome_sequencing/WNuHaU2K">whole-genome sequences</a> indicate this occurs as frequently as approximately once every 4,000 human births.

Nuclear mitochondrial DNA segment open-in-new

Nuclear mitochondrial DNA segment