(英) |
Mariner-like-sequences (MLSs) were isolated from individuals of Bombyx mandarina inhabiting in some regions of China, Korea and Japan by the long PCR methods using the inverted terminal repeat of Hyalophora cecropia MLE as a primer.
The amplified bands were from about 1.3 kbp regarded as the full-length of MLEs to around 2.5 kbp, which were expected to contain some other sequences, rather than MLEs. All the amplified bands were cloned by TA cloning method and representative length of clones were sequenced comprehensively. These sequences thus obtained were trimmed by eliminating other sequences to get the full length of MLEs.
Multiple alignment and phylogenetical analyses reveal that these MLE sequences were divided into two major groups according to the inhabiting places of B. mandarina. Without some exceptions, MLE sequences from the Japanese mandarina composed one unique group (Japanese Group). On the other hand, almost all the MLE sequences of the mandarina from China and Korea settled down in another group (Continental group). Further, the sequences of the mandarina from Fukuoka, Tsushima, and Hokkaido in Japan spread over both of the two distinctive groups.
These results indicated that the MLE sequences in the same Cecropia subfamily might relate with the geographical distribution area of Bombyx mandarina.
Moreover, MLE sequences from some vertebrate species inhabiting in Japan islands situate in the Japanese mandarina group. Even though all of them were disrupted by other elements like L1Bm retrotransposable element, these facts might suggest that the MLEs had transmitted horizontally among phylogenetically remote organisms inhabiting close regions in Japan by the external supplement of transposase after the Japanese mandarina separate independently from the continental groups. |