[Gene rearrangement of mitochondrial genome in the vertebrate]

Up to date, complete mitochondrial genomes of 321 vertebrates are deposited in GenBank. After comparing the sequence data, we summarized the gene arrangements of these species in present study. Of those species, 81 have distinct gene rearrangements all involving tRNA genes. Among them, 9 gene rearrangements display both gene order variation and gene encoding invertion. All observed gene order changes of vertebrate mtDNAs fall into 3 categories characteristically: exchange of position between nearest neighbor.genes or segments; the changes close to control region or the origin of light-strand replication, occasionally accompanying with duplication of control region; or the changes near the region originally characterized as I-Q-M. All birds, snakes,crocodiles and marsupials have their unique gene orders respectively. Gene inversion,another distinguished character of the rearrangement,is commonly indicated by the transfer of tRNA genes from light-strand to heavy-strand, which is more frequently observed in the fish and mammal. Three species from different classes share a complicated inversion phenomenon: all genes encoded by heavy-strand except ND6. For explanation of these rearrangements,two models,"duplication-random deletion" and "recombination", were commonly adopted by scientists. This paper also gives a brief summarization on the mechanism of these models as well as the application of gene rearrangement in phylogenetic studies.