ChromosomeEvolution2013

1、各种克隆以及基因分析法和能够处理的染色体组的大小以染色体组为对以染色体组为对象进行杂交时，由象进行杂交时，由于染色体组中于染色体组中特定特定序列（序列（Alu及及L1等）等）的存在，当探针是的存在，当探针是包含包含Alu 及及L1序列序列时，探针也和目标时，探针也和目标部位以外的染色体部位以外的染色体组中大量存在的组中大量存在的Alu及及L1 进行杂交，进行杂交，会检测出非特异性会检测出非特异性的信号。的信号。 SKYSKY法：用法：用5 5种荧光色素将种荧光色素将人染色体染上不同的颜色。人染色体染上不同的颜色。利用流式细胞术对利用流式细胞术对2424种染种染色体进行分离回收。在为色体进行分离

2、回收。在为各染色体的基因组各染色体的基因组DNADNA建立建立文库后，分别用它们制成文库后，分别用它们制成不同的染色体探针。不同的染色体探针。光谱核型分析光谱核型分析(SKY) CISS法法 将无荧光色素标将无荧光色素标记的记的Alu及及L1与已标与已标记的探针混合进行记的探针混合进行杂交的方法。已标杂交的方法。已标记探针中的记探针中的Alu及及 L1与未标记的与未标记的Alu及及 L1间进行竞争，利间进行竞争，利用未标记的用未标记的 “探针探针”掩蔽存在于染色体掩蔽存在于染色体组中的组中的Alu及及 L1 , 能能除去重复序列引起除去重复序列引起的非特异性信号。的非特异性信号。LINE 与

3、SINE 重复序列L1 与 Alu 重复序列基基 因因 组组 比比 较较 杂杂 交交 法法 (comparative genomic hybridization法，法，CGH法法) ：将细胞中提取的基因组：将细胞中提取的基因组DNA作探针，以作探针，以1号号22号及号及XY染色体的人体染色体为对象，对细胞中产生的染色体拷贝数染色体的人体染色体为对象，对细胞中产生的染色体拷贝数变化进行测定的基因组分析技术。变化进行测定的基因组分析技术。CGH微阵列法微阵列法：将已明确了在染色体上的位置的、包含基因组：将已明确了在染色体上的位置的、包含基因组DNA的人工染色体的人工染色体 (BAC等等)点样在载玻

4、片上而形成的微阵列。点样在载玻片上而形成的微阵列。 一位女性病人一位女性病人 23 对染色体的标准对染色体的标准 G 显带图像显带图像洋葱核型制片洋葱核型制片有功能的人类着丝粒有功能的人类着丝粒着丝粒着丝粒DNA(CEN-DNA)经典的经典的satDNA satDNA家族家族satDNA家族家族 sat星星DNA家族家族48bpsatDNA家族家族Sn5satDNA家族家族着丝粒蛋白质着丝粒蛋白质(CENP)：CENP-A、CENP-B、CENP-C、CENP-E和和CENP-G五种类型五种类型家 族家 族 I ： 由由 4 2 b p 的 单 体 组 成 ， 其 中的 单 体 组 成 ， 其

5、 中 1 7 b p (ACATAAAATATCDAAAGT)为可变区，为可变区，25bp (ACCCAAAAAGTAGTATTATATACTGT)为重复单位为重复单位家族家族II是保守性差的是保守性差的ATTCC重复；重复；家族家族III是较保守的是较保守的ATTCC重复，且与重复，且与l0bp的序列的序列(ATGTCGGGTTG)相间分布。相间分布。 CENP-A：位于着丝点内层并与：位于着丝点内层并与satDNA结合、是结合、是着丝粒特异性的核心组蛋白；着丝粒特异性的核心组蛋白； CENP-B：特异性地与：特异性地与卫星卫星DNA中中17bp的的DNA单单体体(即即CENP-B box)

6、结合。结合。 CENP-C：位于着丝点内层。：位于着丝点内层。 CEXP-G：位于间期的核基质和着丝点内层，整个：位于间期的核基质和着丝点内层，整个细胞周期中始终与着丝粒结合；细胞周期中始终与着丝粒结合； CENP-E：是有丝分裂特异性的组份。：是有丝分裂特异性的组份。 端粒端粒DNA序列序列端粒序列端粒序列:GT链的链的5-3方向总是指向染色体的末端，而方向总是指向染色体的末端，而CA链的链的5-3则方向相反，指向着丝粒则方向相反，指向着丝粒; 端粒重复单位的复制次数不完全均一；端粒重复单位的复制次数不完全均一；端粒序列的链区内有缺口，有游离的端粒序列的链区内有缺口，有游离的3端羟基存在，端

7、羟基存在，可作为聚合酶合成的引物；可作为聚合酶合成的引物； 端粒序列的末端不能进行末端标记，推测其分子未端粒序列的末端不能进行末端标记，推测其分子未端不是游离的。端不是游离的。5-CCCCAA-33-GGGGTT-5TelomereFISH of a DNA probe containing the sequence TTAGGG, which localizes to the telomeres of human chromosomes.A. Demonstration that certain proteins bind specifically to telomeric DNA.Chro

8、mosome territories are not solid entities, and their interior is permeated by a network of nucleoplasmic channels. l metacentricl submetacentricl acrocentricl telocentricl acrocentric with terminal NORl satellited metacentric with interstitial NOR. Left- PericentricRight-paracentric inversion involv

9、ing the NORShape and size of chromosomes altered by reciprocal translocation（相互易位）（相互易位）Insertion (e.g. via transposition).Reciprocal symmetric exchange of segments unequal in sizeTerminal or interstitial deletionShape and size of chromosomes altered by reciprocal translocation Unequal somatic recom

10、bination (sister chromatid exchange) between tandem repeats out of register. Replication slippage and repair of the dsDNA according to the newly synthesized strand (dotted) causes duplication (above) or deletion (below). Breakage-fusion-bridge cycles can alter chromosome size and shape via random di

11、sruption of dicentric chromatids during anaphase. Such disruptions yield deletion, duplication or inversion through fusion of broken ends after replication and another breakage during the next nuclear division. The cycle might stop by healing of breaks when telomeric sequences become attached. Two t

12、ranslocations between three chromosomes are shown. From this meiocyte（性母细胞（性母细胞), the new chromosome segregates together with the other two translocation chromosomes to one pole (arrows directed downward), whereas on the other pole, the wildtype situation is reconstituted (arrows directed upward). S

13、ister chromatids of chromosome arms longer than half of spindle axis extension do not completely separate during mitotic nuclear division. The resulting telophase bridge becomes disrupted by newly growing cell wall and yields deletions (micronuclei) and apoptotic meristem cells.Notice A metacentric

14、chromosome after centric fission yields a telocentric chromosome that becomes truncated at its centric end and eventually forms a novel centromeres, as observed for barley chromosomes in a gametocidal wheat background. Recombinative double-strand break (dsb) repair with insertion (left) of sequences

15、 from other genomic regions before final ligation or with deletions (right) that result from exonucleolytic digestion at break ends before ligation. Alteration of diploid chromosome number by mis-segregation from meiotic multivalents of an individual that is heterozygous for two translocations betwe

16、en a metacentric and two acrocentric chromosomes with breakpoints close to the centromeres. The resulting gametes with reduced (2) or increased (4) chromosome number are viable, provided that the small deletions or duplications concerning the short arms of the acrocentrics can be tolerated. Fusion o

17、f acrocentric chromosomes into metacentric ones is reversible if the telomeric sequences that flank the centromeres remain conserved (left); alternatively, a metacentric chromosome may split into stable telocentrics when the centric breaks are healed by attaching telomeric sequences.Chromosome numbe

18、r reduction from n = 8 to n = 5 during the evolution of A. thaliana. Top left: A. lyrata including centromere and NOR positions, with each chromosome corresponding one of the linkage groups of the ancestral karyotype (AKAK8). Top right: The syntenic regions within the A. thaliana indicate that two translocations (T1 and T2), three fusions (F1F3), and three inversions (I1I3) were involved in the evolution of the A. thaliana karyotype. Bottom: Because I1 represents a pericentric inversion, comprising the entire sort arm of AK2, a subsequent reciprocal