The Comparative Analysis Of The Mitochondrial DNA Control Region Of Four Species Of Strigiformes

In this paper, four species avian complete mitochondrial genomes of Strigiformes were sequenced and analyzed. And the structure, evolution and function of control regions of avian mtDNA as well as tandem duplication sequences were also discussed.The whole mitochondrial DNA control region sequence of Asio flammeus, Asio otus, Athene noctua and Strix aluco were sequenced, which demonstrate that the length of the control region is 3290bp, 2848bp, 2444bp and 1771bp, respectively. It is also interestingly found that Asio flammeus has the largest control region among all avian mitochondrial DNA control region sequenced so far. In addition, the base composition and the organization of control region of the four species are identical to the other reported birds, with obviously AT-rich. Based on the differential frequencies of base substitutions, their mitochondrial control region may be divided into three domains: two variable domain â…  and â…¢ as well as a central conserved domain â…¡. Some conserved sequence motifs are also found in all three domains of control region of the two owls. We further analyzed to find that the 3' end of control region of the four owls contains many tandem duplication sequences. In Asio flammeus, the repeated sequences consisted of a 126 bp sequence repeated seven times and a 78 bp sequence repeated fourteen times, there are 99 bp spaces between the two sets of repeats. while in Asio otus, there are also two repeated sequences, namely a 127 bp sequence repeated eight times and a 78 bp sequence repeated six times, with 55bp spaces between the two sets of repeats. Furthermore, the control region of Athene noctua contains three sets of repeats: a 89 bp sequence repeated three times, a 77 bp sequence repeated four times and a 71 bp sequence repeated six times, there are only 2 bp spaces between 89 bp units and 77 bp units, while the 77 bp repeats and 71 bp repeats are secluded by 64 bp sequence. Strix aluco, however, has only one repeated sequence, that is a 78 bp sequence repeated five times. Our results seem to indicate that the origin of tandem repeats of mtDNA control region may result...