What is "numt"

NUMT, pronounced "new might,” is short for “nuclear mitochondrial DNA segment” and describes a transposition of any type of cytoplasmic mitochondrial DNA into the nuclear genome of the eukaryotic organisms. More and more NUMT sequences, with different size and length, in the diverse number of Eukaryotes, have been detected as more whole genome sequencing of different organisms accumulate. In fact, NUMTs have often been unintentionally discovered by researchers who were looking for 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 germline stability and mitochondria number.

After the release of the mtDNA to the cytoplasm, due to the mitochondrial alteration and morphological changes, mtDNA is transferred into the nucleus by one of the various predicted methods and are eventually inserted by double-stranded break repair processes into the nuclear DNA. Not only has any correlation been found between the fraction of noncoding DNA and NUMT abundance in the genome but NUMTs are also proven to have non-random distribution and a higher likelihood of being inserted in the certain location of genome compare to others. Depending on the location of the insertion, NUMTs might perturb the function of the genes. In addition, De novo integration of NUMT pseudogenes into the nuclear genome has an adverse effect in some cases, promoting various disorders and aging. 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 Saccharomyces cerevisiae. 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 phylogenetic analyses, scientists have used NUMTs as the genetic markers to figure out the relative rate of nuclear and mitochondrial mutation and recreating the evolutionary tree.