Comparative Analysis Of Mitochondrial Fragments Transferred To The Nucleus In Vertebrate

Content: Mitochondrial DNA sequences are frequently transferred to the nucleus giving rise to the so-called NUMT (nuclear mitochondrial DNA segments) which not only homologous to mtDNA but also no expression functions. Mitochondrial pseudogenes are greatly researched in plants, insects and mammals, however, which in Aves has a less research. With the concurrent developments of polymerase chain reaction (PCR) and DNA sequencing technology, the mitochondrial DNA (mtDNA) has become a very useful molecular marker for studying avian systematics and evolutionary biology. Currently, there are only 244 numts containing gained by lab in six orders (Anseriformes, Columbiformes, Falconiformes, Galliformes, Charadriiformes and Passeriformes) of Aves in public database (GenBank).NCBI-BLASTN was carried out with mitochondrial and corresponding nuclear genome of nine species in vertebrates (Gallus gallus (NC₀01323), Mus musculus (NC₀01665), Rattus norvegicus (NC₀05089), Sus scrofa (NC₀00845), Bos Taurus (NC₀06853), Canis familiaris (NC₀02008), Rhesus macaque (NC₀05943), Pan troglodytes (NC₀01643), Homo sapiens (NC₀01807)). The sequences with high homology were considered as'numts'. In our findings, the number of numts in Gallus gallus, Mus musculus, Rattus norvegicus, Sus scrofa, Bos Taurus, Canis familiaris, Rhesus macaque, Pan troglodytes and Homo sapiens were 15, 44, 17, 21, 39, 69, 92, 159 and 147, respectively. The sequences of numts in Rhesus macaque, Pan troglodytes and Homo sapiens span 100 % of the entire mammalian mitochondrial genome. The reconstructed frequency of mitochondrial gene transfer to nucleus shows rRNA gene has more frequency than other mitochondrial gene. Using the RepeatMasker program, we detected the transposable elements in the flanking regions of each numt. The result shows less than 5 % of nuclear sequence were repetitive elements. Furthermore, these numts are considered to independent insertion from the mitochondria into the nucleus in Gallus gallus. The GC content of 5' and 3' - flanking region of numts in nine species is less than 44 %. The analysis of numts flanking sequences provides a valuable understand for future study in mechanism of motichondrial transfer to nucleus and the site of numt integration.