Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành y học dành cho các bạn tham khảo đề tài: Evolution of the rpoB-psbZ region in fern plastid genomes: notable structural rearrangements and highly variable intergenic spacers | Gao et al. BMC Plant Biology 2011 11 64 http 1471-2229 11 64 BMC Plant Biology RESEARCH ARTICLE Open Access Evolution of the rpoB-psbZ region in fern plastid genomes notable structural rearrangements and highly variable intergenic spacers Lei Gao 1 Yuan Zhou1 Zhi-Wei Wang1 Ying-Juan Su2 and Ting Wang1 Abstract Background The rpoB-psbZ BZ region of some fern plastid genomes plastomes has been noted to go through considerable genomic changes. Unraveling its evolutionary dynamics across all fern lineages will lead to clarify the fundamental process shaping fern plastome structure and organization. Results A total of 24 fern BZ sequences were investigated with taxon sampling covering all the extant fern orders. We found that i a tree fern Plagiogyria japonica contained a novel gene order that can be generated from either the ancestral Angiopteris type or the derived Adiantum type via a single inversion ii the trnY-trnE intergenic spacer IGS of the filmy fern Vandenboschia radicans was expanded 3-fold due to the tandem 27-bp repeats which showed strong sequence similarity with the anticodon domain of trnY iii the trnY-trnE IGSs of two horsetail ferns Equisetum ramosissimum and E. arvense underwent an unprecedented 5-kb long expansion more than a quarter of which was consisted of a single type of direct repeats also relevant to the trnY anticodon domain and iv ycf66 has independently lost at least four times in ferns. Conclusions Our results provided fresh insights into the evolutionary process of fern BZ regions. The intermediate BZ gene order was not detected supporting that the Adiantum type was generated by two inversions occurring in pairs. The occurrence of Vandenboschia 27-bp repeats represents the first evidence of partial tRNA gene duplication in fern plastomes. Repeats potentially forming a stem-loop structure play major roles in the expansion of the trnY-trnE IGS. Background In contrast to nuclear and mitochondrial genomes plant plastid .
