翼手目四个类群的比较分子细胞遗传学研究

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	翼手目四个类群的比较分子细胞遗传学研究
其他题名	Comparative molecular cytogenetic studies of four bat families (Order Chiroptera)
	敖磊
学位类型	博士
导师	杨凤堂
	2006-06
学位授予单位	中国科学院研究生院
学位授予地点	北京
关键词	翼手目蝙蝠染色体涂色核型进化比较染色体图谱
摘要	翼手类(Order Chiroptera)是现生哺乳动物中唯一真正具有空中飞翔能力的动物；同时，它也是哺乳动物中为数不多的具有回声定位功能的几个分类类群之一。现存的翼手目动物约有1100种，占整个哺乳动物种类的20％以上，是哺乳动物中仅次于啮齿目的第二大目。尽管对于翼手目系统发育已经进行了大量的形态学和分子系统学等方面研究，但是翼手目中主要类群的系统发育关系尚存在着许多争议。进化过程中发生的染色体重排在揭示物种的系统发育关系中起到非常重要的作用。种间染色体涂色可以准确、快速、直观地鉴定物种进化过程中发生的大规模染色体重排，已成为在全基因组水平上比较研究哺乳动物核型多样性及其起源和演化的首选方法。利用染色体涂色可以构建不同物种间的比较染色体图谱，通过分析进化过程中保守的染色体片段在不同类群物种核型中的分布和排列方式，可以推导各类群可能的祖先核型，并重建伴随物种形成所发生的基因组变化历史，包括染色体重排的类型、速率和核型演化的趋势。但是，目前关于翼手目染色体涂色研究还很少，至今仍不能为翼手目各级分类水平上的系统发育关系研究提供系统完整的细胞遗传学证据。本研究利用大鼠耳蝠染色体特异涂色探针，通过种间染色体涂色，首次构建了狐蝠科、菊头蝠科、蹄蝠科和蝙蝠科代表物种间的比较染色体同源图谱，并且将它们与之前发表的用人的染色体探针构建的比较染色体图谱进行整合。通过分析这些物种之间保守染色体片段的分布，推测翼手目动物在核型进化过程中所发生的染色体重排的类型和数量，以期为研究翼手目的系统发育关系提供细胞遗传学证据。研究结果表明： 1. 翼手目动物的大多数染色体臂具有高度保守性，罗伯逊易位是其核型进化的主要机制。此外，倒位也是翼手目染色体进化过程中常见的染色体重排方式。 2. 小蝙蝠亚目的菊头蝠科和蹄蝠科与大蝙蝠亚目的狐蝠科亲缘关系更为接近，而与小蝙蝠亚目其它科的亲缘关系较远。 3. 菊头蝠科和蹄蝠科应该各自作为独立的科，但这两个科拥有一个共同的细胞遗传学衍生特征，这一特征在翼手目其它科中并未发现，表明它们之间有非常紧密的系统发育关系。 4. 菊头蝠科的祖先核型可能并不是前人所推测的全由端着丝粒染色体构成的2n＝62的核型；很有可能是包含有双臂染色体的，2n低于62的核型。 5. 三叶小蹄蝠比中蹄蝠保留更多的祖先染色体特征，其核型蹄蝠科中较为原始的核型。 6. 着丝粒融合是蝙蝠科物种核型演化的主要机制。蝙蝠科的祖先核型并不是类似于2n=44鼠耳蝠的核型，而可能更类似于棕蝠的2n＝50核型，由全端着丝粒染色体构成。 7. 除着丝粒融合外，异染色质的扩增也是蝙蝠科扁颅蝠属和山蝠属的染色体进化方式之一。 8. 绒山蝠与三种亚洲的伏翼共有两个同源染色体片段联合（MMY 8＋11和9＋13）,提示蝙蝠科的山蝠属和伏翼属有非常紧密的亲缘关系。 9. MMY 9 + 23和MMY 18＋19 这两个保守的同源染色体片段联合是蝙蝠科扁颅蝠属的细胞遗传学鉴定特征。通过翼手目这些动物的染色体涂色研究，我们不但在全基因组的水平上揭示了翼手目几个主要类群代表动物的核型系统发育关系，而且所构建的比较染色体图谱将有助于基因组的序列信息从已测序物种（人）向序列信息较少的翼手目物种转移，这些研究结果也可以为翼手目的分类、物种鉴定、系统发育关系和生物医学研究（如SARS病毒）等提供基础性资料。
其他摘要	Abstract: Bats (Order Chiroptera), the only mammals capable of self-powered flight and sophisticated laryngeal echolocation, is the second largest family in mammals, containing 1,100 species, i.e., more than 20% of extant mammals. Although the taxonomic and phylogenetic studies based on a large number of anatomical and molecular comparisons have been conducted extensively in this order, the systematics of bats remains controversial. Chromosome rearrangements that have occurred during the process of karyotype evolution have been widely used in recent phylogenetic studies. Cross-species chromosome painting (also known as Zoo-FISH) is a rapid and accurate way to establish genome-wide homology among different species and its increasing application in comparative cytogenetics has greatly improved our understanding of karyotype evolution in mammals. However, chromosome painting has only been applied to a few species in bats. I have constructed comparative chromosomal maps between the representative species from four bat families, including Pteropodidae, Rhinolophidae, Hipposideridae and Vespertilionidae by using a complete set of chromosome-specific painting probes from Myotis myotis for the first time in the world. The FISH data has enabled the integration of chromosomes of these species into the previously established comparative maps constructed with human probes and improved our understanding on the karyotypic relationships and genome phylogeny of these bat species. The FISH results indicate that: 1. There is a high degree of whole chromosomal arm conservation in the order Chiroptera. Extensive Robertsonian translocations in different combinations are the main mode of karyotype evolution in the order Chiroptera. In addition, inversion is a common mode of chromosome rearrangement during chromosome evolution of bats. 2. The superfamily Rhinolophoidea is more closely related to megachiroptera than to any other microchiropteran clades. 3. Rhinolophoidae and Hipposideridae should be treated as the separate families and share one common cytogenetic synapomorphic feature, which does not exist in all other families. This finding strongly indicates a very close phylogenetic relationship between Rhinolophoidae and Hipposideridae. 4. The diploid chromosome number of the presumed rhinolophid ancestor could be lower than 2n = 62. 5. The chromosomes of Aselliscus stoliczkanus show more plesiomorphic feature than those of Hipposideros larvatus. Thus, Aselliscus stoliczkanus is one of the most plesiomorphic hipposiderids. 6. Centric fusions are the predominant mechanisms of chromosome evolution in the family Vespertilionidae. The ancestral karyotype of the family Vespertilionidae is likely a 2n=50 karyotype similar to the Eptesicus karyotype that consists of acrocentric autosomes, rather than the 2n=44 karyotype that is retained by Myotis bat. 7. Besides centric fusions, the amplification of heterochromatic materials is a common mode of chromosome evolution in the genera Tylonycteris and Nyctalus 8. N. velutinus shares two fusion chromosomes (MMY 8+11 and 9+13) with the three Asian Pipistrellus species, indicating a very close relationship between Nyctalus and Pipstrellus 9. The MMY 9+23 and 18+19 conserved syntenic associations could be the cytogenetic signatures for the genus Tylonycteris. In addition to illustrating the karyotypic relationships of the bats, the integrated chromosomal maps presented here could serve as a frame work for the future taxonomical, evolutionary and biomedical researches and will aid the transfer of genomic information from map-rich species (human etc) to map-poor species (bats etc).
语种	中文
文献类型	学位论文
条目标识符	http://ir.kiz.ac.cn/handle/152453/6262
专题	其他
推荐引用方式 GB/T 7714	敖磊. 翼手目四个类群的比较分子细胞遗传学研究[D]. 北京. 中国科学院研究生院,2006.

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