The mitochondrial DNA control region comparison studies of four hinged turtles and its phylogentic significance of the genus Cuora sensu lato (Testudinata: Geoemydidae)

The complete sequences of the mitochondrial DNA (mtDNA) control region (CR) of Cistoclemmys flavomarginata, Cistoclemmys galbinifrons, Cuora aurocapitata and Cyclemys atripons were amplified by long-polymerase chain reaction (Long-PCR). The lengths were 1207 bp, 1722 bp, 1379 bp and 980 bp, respectively. Combining with the CR sequence of Pyxidea mouhotii (DQ659152), we compared the CR structure, and identified three functional domains (TAS, CD and CSB) in which the conservation sequences (TAS, CSB-F, CSB-1, CSB-2 and CSB-3) were also successfully identified according to their homology to those of other turtles. These 5 turtles have the identical CSB-2 and CSB-3 sequences, and 4 of them have the same CSB-1 sequence while there is one base transversion (T → A) in Cy. atripons . We analyzed the variable number of tandem repeat (VNTR) sequences or microsatellites at the 3′ end of CR. The motifs of tandem repeats (7 types) are made up of 2–8 nucleotides, and the copy numbers are from 4 to 48. All of the 5 turtles except Cy. atripons have the “TATTATAT” repeats and are ended by TA. The results of CR structure analysis displayed that the Cuora, Cistoclemmys , and Pyxidea have many similarities, but differ from Cyclemys . With Indotestudo elongate (DQ080043) and Indotestudo forstenii (DQ080044) as outgroups, using the CR sequences (1123bp) excluded the microsatellites at the 3′ end of CR, we constructed the molecular phylogenetic trees using the MP, ML and BI methods. The results showed that there was a strong support to the monophyly of the Cuora group consisting of Cuora , Cistoclemmys and Pyxidea , which has a close relationship with Mauremys and Chinemys but far from Cyclemys , which are consistent with the analysis of the CR structure of the 5 turtles.