利用比较染色体涂色和BAC定位技术探讨麂属动物染色体的起源和演化
文献类型：学位论文
| 作者 | 迟建祥 |
| 学位类别 | 博士 |
| 答辩日期 | 2005-04 |
| 授予单位 | 中国科学院研究生院 |
| 授予地点 | 北京 |
| 导师 | 杨凤堂 |
| 关键词 | 赤麂 小鹿 串联融合 BAC文库 林麝 大额牛 |
| 其他题名 | The chromosome evolution of muntjacs revealed by comparative chromosome painting and BAG mapping |
| 中文摘要 | 比较细胞遗传学研究发现物种的形成过程往往伴随着核型结构的变化，各种鹿属动物染色体的巨大差异正是很好的例证'赤魔的染色体被证明是由具有端着丝粒的祖先染色体经过多次的串联融合进化而来的。根据祖先染色体的形态和连接方式，可以将染色体串联融合主要分为三类：着丝粒一着丝粒融合，着丝粒一端粒融合和端粒一端粒融合。经典细胞遗传学，比较染色体涂色，卫星DNA序列和部分融合位点序列比较研究都支持串联融合假说。但串联融合的类型和分子机制迄今没有完全弄清楚。本论文旨在对魔属动物的串联融合类型和分子机制进行研究，分为两个部分：一、通过比较染色体涂色的方法，建立小鹿一林察一大额牛的比较染色体图谱，结合以前发表的结果来阐明鹿科（小魔）与牛科（大额牛），寮科（林磨）之间的核型关系；二、建立赤鹿的全基因组BAc文库，通过克隆定位的方法确立在赤魔的染色体进化过程中所发生的串联融合类型，并对其机制进行探讨。主要结果如下：利用小鹿的染色体特异探针与林寮，大额牛的染色体进行杂交，首次建立了小鹿一大额牛，小魔一林察的核型对比关系。结果显示小鹿的1-5、11号染色体均与林集和大额牛的多段染色体同源。结合高分辨的G带比较，发现小魔1-5和11号染色体上的与林爵和大额牛对应的所有同源片断在小鹿染色体上呈着丝粒一端粒连接排列。从而进一步证明小鹿的1-5和11号染色体是由2n=70的祖先核型通过染色体的着丝粒一端粒串联融合方式进化而来的。建立了我国第一个赤魔全基因组BAC文库，该文库由124800个克隆组成。大部分插入片段的大小在100-145kb之间，片段的平均大小为12＜0kb。克隆定位显示克隆的分布与小鹿染色体大小成正比关系，说明整个文库没有染色体的偏倚，文库为整个基因组的6倍，覆盖率几乎为100％。通过赤鹿BAC克隆在小魔和赤鹿染色体上的精确定位，使我们得以准确判断小鹿染色体在赤鹿染色体同源片段上的连接方式，并确定串联融合的类型。结果进一步支持赤鹿的核型是由一个2n=70祖先核型通过着丝粒一端粒的融合方式进化而来的。 |
| 英文摘要 | Comparative cytogenctic studies demonstrate that speciation events are often accompanied by some changes in karyotypes and the drastic karyotypic differences among muntjacs have been regarded as the paradigm for such speciation processes.. The Indian muntjac's grant chromosomes have been shown to originate from numerous ancestral acrocentric chromosomes via multiple fusion events. According to the chromosome morphology and fusion orientation, the tandem fusion events are classified into three types: centromere-centromere; centromere-telomere and telomere-telomere. The tandem chromosome fusion hypothesis of muntjacs has gained supports from classic cytogenetics (banding comparison), comparative chromosome painting, satellite DNA FISH and alignments of genomic sequences from fusion regions. However, some key questions on karyotype evolution of muntjacs remain unanswered: which type of tandem fusions has occurred in the muntjacs and what is the molecular mechanism that underlies the tandem fusion events? These two questions form the focus of my research project. The whole thesis is divided into two parts: First: Compararive karyotyping between Chinese muntjac and forset musk deer, Chinese muntjac and gayal were established respectively. Combined with the published results, our results provide new insights into the karyotypic relationship among Cervidae, Bovidae and Moschidae. Second: A 6-times Indian muntjac BAG library was constructed. The type of tandem fusions occurred during the Indian muntjac evolution was defined by compative mapping of BAC clones. The main results are as follows: o Comparative chromosome painting and banding analyses among Chinese muntjac, forest musk deer and gayal have enabled the determination of evolutionary conserved segments in Chinese muntjac: Chinese muntjac (MRE) chromosome specific paints 1-5 and 11 each delineated more than one homologous chromosome segments in the forest musk deer and gayal genomes. The hig-resolution G-banding comparisons among Chinese muntjac, forest musk deer and gayal demonstrate that Chinese muntjac chromosome 1-5 and 11 are originated through centromere-to-centrornere fusion of ancestral acrocentric chromosomes. o An Indian muntjac BAC library consisting of 124800 clones has been constructed. The sizes of DNA inserts of most BAC clonesare around 100-145kb with the average of 120kb* FISH mapping of randomly-selected clones on Chinese muntjac chromosomes detected no chromosome bias in the BAC library and the coverage of the BAC library is nearly 100% of Indian muntjac genome. About 70 STSs are generated by end sequencing of the clones located near the fusion sites on Indian muntjac chromosomes, thus providing good genetic markers for further study. ·Defining the orientation of conserved segments in Indian muntjac with BAC clones: The results show that the karyotype of Indian muntjac could have derived from a 2n=70 karyotype by extensive centronmere-to-telomere fusion events. |
| 语种 | 中文 |
| 公开日期 | 2010-10-15 |
| 源URL | [http://159.226.149.42:8088/handle/152453/6184]  |
| 专题 | 昆明动物研究所_其他 |
| 推荐引用方式 GB/T 7714 | 迟建祥. 利用比较染色体涂色和BAC定位技术探讨麂属动物染色体的起源和演化[D]. 北京. 中国科学院研究生院. 2005. |
入库方式： OAI收割
来源：昆明动物研究所
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