Isolation And Characterization Of Ty1/Copia-like Reverse Transcriptase Sequences From Panax Species

Ty1-copia-like sequences were amplified from two relative Panax species (Panax ginseng and Panax quinquefolius) genomic DNA, by PCR with degenerate oligonucleotide primers corresponding to highly conserved domains in the Ty1-copia-like retrotransposons. PCR fragments of roughly 246bp were isolated and cloned, and 83 clones were obtained. According to alignment and phylogenetic analysis, all sequences were divided into ten groups. Among these families, seven ones were enclosed in phylogenetic tree and three ones had only one sequence. The nucleotide sequence similarity shown by computer analysis between inter- and intra-group was in a wide range, which indicates high level of sequence heterogeneity among these clones and groups. Among these sequences, 47 clones had unique nucleotide sequences (intact sequences), and the others had a frameshift, a stop condon, or both. Southern analysis revealed distribution of these sequences in two panax species. Methylation analysis showed there were high level of methylation in two panax species...