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 (mitochondrial DNA). 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.