本项目系统研究了淫羊藿基因组中转座子重复序列的组成及其在染色体上的分布情况，在此基础上开发了转座子分子标记。取得的主要研究结果有：.1）随机选取了672个箭叶淫羊藿的基因组DNA克隆进行测序，共得到了725 kb的基因组序列，约占整个箭叶淫羊藿基因组大小的0.0157%。.2）所得到的序列当中，转座子重复序列是最主要的重复序列类型，占到了所有重复序列的82.31%，主要由Ty3-gypsy和Ty1-copia组成。.3）利用兼并引物从10个淫羊藿物种克隆copia-rt序列，并构建NJ系统进化树，结果表明有一类copia反转座子在近期转座爆发，可能是导致淫羊藿基因组巨大的原因之一。.4）在淫羊藿粗线期染色体上FISH定位Ty1-copia和Ty3-gypsy转座子，结果表明这些重复序列在淫羊藿染色体上属于随机分布，但主要集中分布在染色体末端。.5）筛选到19对多态性较高的iPBS转座子分子标记，用于箭叶淫羊藿物种自然变异类型分析。

Epimedium is a member of the Berberidaceae family of basal eudicot plants, widely distributed and used as a traditional medicinal plant in China with a long history for its great therapeutic effects on many diseases. Recent data shows that E. sagittatum has an extremely large genome, with a haploid genome size of 4496 Mbp, divided into a small number of only 12 diploid chromosomes (2n = 2x = 12). However, little is known about Epimedium genome structure and composition. Major achievements are as following: 1) High-quality of 725 kb genomic sequences were obtained from 672 randomly selected plasmid clones of E. sagittatum genomic DNA, representing 0.0157% of the whole genome. Analysis of the sampled genomic sequences comprised at least 77.91% repetitive DNA elements and 1.96% confirmed annotated gene sequences, with a total GC% content of 39%. Retrotransposons represented the major class of transposable element (TE) repeats identified (65.70% of all TE repeats), particularly LTR (Long Terminal Repeat) retrotransposons (53.36% of all TE repeats)..2) The pairwise nucleotide diversity (π) within a species of rt fragments ranged from 0.251 to 0.428 for 10 Epimedium species. Phylogenetic analysis revealed four major clades, with the largest subclade containing 72 sequences of relatively low nucleotide diversity. The relatively low sequence heterogeneity of Ty1-copia-rt sequences implies that the Epimedium genomes have experienced a relatively large-scale proliferation event of copia elements, which could be one of the major forces resulting in the large genome size of Epimedium species..3) FISH indicated Ty1-copia retrotransposons are distributed unevenly along the pachytene chromosomes of E. wushanense and E. sagittatum, mostly associated with the pericentromeric and terminal heterochromatin. .4) Nineteen iPBS primers were selected to analyze the natural variation of 11 E. sagittatum species. This work is still under investigation and the following publication will be reported later..The study provided the first insight into the composition and structure of the Epimedium genome, and will facilitate the functional genomic analysis of this valuable medicinal plant.

本项目系统研究了淫羊藿基因组中转座子重复序列的组成及其在染色体上的分布情况，在此基础上开发了转座子分子标记。取得的主要研究结果有：1）随机选取了672个箭叶淫羊藿的基因组DNA克隆进行测序，共得到了725 kb的基因组序列，约占整个箭叶淫羊藿基因组大小的0.0157%。2）所得到的序列当中，转座子重复序列是最主要的重复序列类型，占到了所有重复序列的82.31%，主要由Ty3-gypsy和Ty1-copia组成。3）利用兼并引物从10个淫羊藿物种克隆copia-rt序列，并构建NJ系统进化树，结果表明有一类copia反转座子在近期转座爆发，可能是导致淫羊藿基因组巨大的原因之一。4）在淫羊藿粗线期染色体上FISH定位Ty1-copia和Ty3-gypsy转座子，结果表明这些重复序列在淫羊藿染色体上属于随机分布，但主要集中分布在染色体末端。5）筛选到19对多态性较高的iPBS转座子分子标记，用于箭叶淫羊藿物种自然变异类型分析。