植物性染色体的起源至今仍是一个未解之谜。反转座子作为移动的基因组成分可能激发了植物性染色体的早期起源和演化。利用染色体微切割微克隆技术，我们初步从石刁柏Y染色体上分离和鉴定了一个具有转录活性的Ty1-copia -like反转座子序列SeqY。在此基础上，本项目以石刁柏（2n=20，雌雄异株）及其同属种文竹（2n=20，花两性）为材料，利用DNA文库筛选方法分离SeqY全长序列并进行结构分析；结合DAPI带分带技术鉴定石刁柏性染色体异染色质分布模式；通过Southern杂交、DNA和染色质Fiber-FISH、RT-PCR、DNA和组蛋白甲基化及组蛋白乙酰化免疫荧光检测技术比较分析SeqY在石刁柏和文竹基因组内活性变化及其与石刁柏Y染色体和文竹相关染色体插入区域的表观修饰模式之间的关系。并综合分析石刁柏Y染色体演化过程中反转座子插入激发的性染色体异染色质化的表观修饰特征。

The mechanism of plant sex chromosome origin and evolution is unclear at present. As the mobile elements of the genome, retrotransposon may trigger the origin and evolution of plant sex chromosome. In this project, SeqY, which with Ty1-copia retrotransposon and transcription features, was isolated and identified from Asparagus officinalis with the chromosome microdissection and microcloning technique. We would like to use A. officinalis (2n=20, dioecious) and A. setaceus (2n=20, bisexual flower) as material, analyze the heterochromatin distribution pattern on A. officinalis sex chromosome with the methods of DAPI (4'6-diamidino-2- phenylindole) painting; using Southern blotting, DNA and chromatin Fiber-FISH(fluorescence in situ hybridization), RT-PCR, DNA and histone methylation immunofluorescence assay and histone acetylation immunofluorescence assay to comprehensively compare and analyze the activity variation of this retrotransposon in A. officinalis and A. setaceus; Furthermore, to study the relationship of retrotransposon activity and the epigenetic pattern of the insertion flanking region of A. officinalis Y chromosome and A. setaceus chromosome. Finally, we wish to comprehensively analyze the epigenetic mechanism of Y chromosome heterochromatinization promoted by retrotransposon insertion during the evolution of A. officinalis Y chromosome.