6 染色体的数量和结构的变化
合集下载
相关主题
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
2018/11/16 Variation in Chromosome Number and Structure 8
One procedure, called G banding, gives dark bands that correspond roughly to the bright bands obtained with quinacrine; another procedure, called R banding, gives the reverse pattern—dark bands that correspond roughly to light G bands. A third procedure, called C banding, stains the region around the centromere of each chromosome.
2018/11/16 Variation in Chromosome Number and Structure 16
Organisms in which a particular chromosome, or chromosome segment, is under- or overrepresented are said to be aneuploid (非 整倍体). These organisms therefore suffer from a specific genetic imbalance.
The karyotype of a human male stained to reveal bands on each of the chromosomes.
2018/11/16 Variation in Chromosome Number and Structure 14
3. Cytogenetic Variation: An Overview
2018/11/16
Variation in Chromosome Number and Structure
3
Section 1
Cytological Techniques
Geneticists use stains to identify specific chromosomes and to analyze their structures.
G bands
Like quinacrine, Giemsa creates a reproducible pattern of bands on each chromosome. However, the nature of the banding pattern depends on how the chromosomes were prepared prior to staining.
The phenotypes of many organisms are affected by changes in their cells; sometimes even changes in part of a chromosome can be significant. These numerical changes are usually described as variations in the ploidy (倍数) of the organism.
Chapter 6
Variation in Chromosome Number and Structure
1 2018/11/16 Variation in Chromosome Number and Structure
Chromosomes, Agriculture, and Civilization
Mosaic trisomy of chromosome 8. Note eversion (外翻) of lower lip, deep furrows on soles, and CT scan show absence of corpus callosum (胼胝体).
2018/11/16 Variation in Chromosome Number and Structure 17
2018/11/16 Variation in Chromosome Number and Structure 4
1. Analysis of Mitotic Chromosomes
Preparation of cells for cytological analysis.
2018/11/16 Variation in Chromosome Number and Structure 5
2018/11/16
Variation in Chromosome Number and Structure
18
A piece of one chromosome may be fused to another chromosome, or a segment within a chromosome may be inverted with respect to the rest of that chromosome. These structural changes are called rearrangements. Because rearrangements segregate irregularly during meiosis, they are often associated with aneuploidy.
2018/11/16
人类染色体数目的确定者
印尼华人
12
他们其实都不是真正的中国人！
Variation in Chromosome Number and Structure
This chart of chromosome cutouts is called a karyotype (核型).
2018/11/16 Variation in Chromosome Number and Structure 13
Until the late 1960s and early 1970s, chromosome spreads were stained with Feulgen’s reagent, a purple dye that reacts with the sugar molecules in DNA, or Chromosomes of the with aceto-carmine (乙 incense cedar (Calocedrus 酸洋红), a deep red dye. decurrens) 北美翠柏stained with aceto-carmine.
2018/11/16
Variation in Chromosome Number and Structure
10
2. The Human Karyotype
Diploid human cells contain 46 chromosomes— 44 autosomes and two sex chromosomes, which are XX in females and XY in males. At mitotic metaphase, each of the chromosomes can be recognized by its size, shape, and banding pattern. The largest autosome is number 1, and the smallest is number 21. The X chromosome is intermediate in size, and Y chromosome is about the same size as chromosome 22.
2018/11/16 Variation in Chromosome Number and Structure 6
Chromosomes that have stained with quinacrine show a characteristic pattern of bands. However, because quinacrine is a fluorescent compound, Metaphase chromosomes the band appear only of the plant Allium when the chromosomes carinatum, stained with are exposed to quinacrine (奎纳克林， ultraviolet light. 阿的平) to reveal Q band.
2018/11/16 Variation in Chromosome Number and Structure 7
The most popular of these uses Giemsa stain, a mixture of dyes named after its inventor, Gustav Giemsa.
2018/11/16 Variation in Chromosome Number and Structure 11
徐道觉 (Tao Chiuh Hsu, 1917-2003)
蒋有兴 (Joe Hin Tjio，1919-2001)
低渗法染色体分散技术发现者
浙江大学农学院毕业生、谈家 桢的学生、美籍华人
The distinction between aneuploidy and polyploidy is that aneuploidy refers to a numerical change in part of the genome, usually just a single chromosome, whereas polyploidy refers to a numerical change in a whole set of chromosomes. Aneuploidy implies a genetic imbalance, but polyploidy does not.
2018/11/16
Variation in Chromosome Number and Structure
2
Chapter Outline
Cytological Techniques
PBaidu Nhomakorabealyploidy (多倍体)
Aneuploidy (非整倍体)
Rearrangements of Chromosome Structure
2018/11/16
Variation in Chromosome Number and Structure
15
Organisms with complete, or normal, sets of chromosomes are said to be euploid (整倍体). Organisms that carry extra sets of chromosomes are said to be polyploid (多倍 体), and the level of polyploidy is described by referring to a basic chromosome number, usually denoted n. Thus, diploid, with two basic chromosomes sets, have 2n chromosomes; triploids, with three sets, have 3n; tetraploids, with four sets; have 4n; and so forth.
2018/11/16 Variation in Chromosome Number and Structure 9
Metaphase human chromosomes stained with acridine orange (吖啶橙) to show R banding. Metaphase chromosome of the Melipona rufiventris (卖 蜂), M. mondury and M. seminigra fuscopilosa stained to show C banding.
One procedure, called G banding, gives dark bands that correspond roughly to the bright bands obtained with quinacrine; another procedure, called R banding, gives the reverse pattern—dark bands that correspond roughly to light G bands. A third procedure, called C banding, stains the region around the centromere of each chromosome.
2018/11/16 Variation in Chromosome Number and Structure 16
Organisms in which a particular chromosome, or chromosome segment, is under- or overrepresented are said to be aneuploid (非 整倍体). These organisms therefore suffer from a specific genetic imbalance.
The karyotype of a human male stained to reveal bands on each of the chromosomes.
2018/11/16 Variation in Chromosome Number and Structure 14
3. Cytogenetic Variation: An Overview
2018/11/16
Variation in Chromosome Number and Structure
3
Section 1
Cytological Techniques
Geneticists use stains to identify specific chromosomes and to analyze their structures.
G bands
Like quinacrine, Giemsa creates a reproducible pattern of bands on each chromosome. However, the nature of the banding pattern depends on how the chromosomes were prepared prior to staining.
The phenotypes of many organisms are affected by changes in their cells; sometimes even changes in part of a chromosome can be significant. These numerical changes are usually described as variations in the ploidy (倍数) of the organism.
Chapter 6
Variation in Chromosome Number and Structure
1 2018/11/16 Variation in Chromosome Number and Structure
Chromosomes, Agriculture, and Civilization
Mosaic trisomy of chromosome 8. Note eversion (外翻) of lower lip, deep furrows on soles, and CT scan show absence of corpus callosum (胼胝体).
2018/11/16 Variation in Chromosome Number and Structure 17
2018/11/16 Variation in Chromosome Number and Structure 4
1. Analysis of Mitotic Chromosomes
Preparation of cells for cytological analysis.
2018/11/16 Variation in Chromosome Number and Structure 5
2018/11/16
Variation in Chromosome Number and Structure
18
A piece of one chromosome may be fused to another chromosome, or a segment within a chromosome may be inverted with respect to the rest of that chromosome. These structural changes are called rearrangements. Because rearrangements segregate irregularly during meiosis, they are often associated with aneuploidy.
2018/11/16
人类染色体数目的确定者
印尼华人
12
他们其实都不是真正的中国人！
Variation in Chromosome Number and Structure
This chart of chromosome cutouts is called a karyotype (核型).
2018/11/16 Variation in Chromosome Number and Structure 13
Until the late 1960s and early 1970s, chromosome spreads were stained with Feulgen’s reagent, a purple dye that reacts with the sugar molecules in DNA, or Chromosomes of the with aceto-carmine (乙 incense cedar (Calocedrus 酸洋红), a deep red dye. decurrens) 北美翠柏stained with aceto-carmine.
2018/11/16
Variation in Chromosome Number and Structure
10
2. The Human Karyotype
Diploid human cells contain 46 chromosomes— 44 autosomes and two sex chromosomes, which are XX in females and XY in males. At mitotic metaphase, each of the chromosomes can be recognized by its size, shape, and banding pattern. The largest autosome is number 1, and the smallest is number 21. The X chromosome is intermediate in size, and Y chromosome is about the same size as chromosome 22.
2018/11/16 Variation in Chromosome Number and Structure 6
Chromosomes that have stained with quinacrine show a characteristic pattern of bands. However, because quinacrine is a fluorescent compound, Metaphase chromosomes the band appear only of the plant Allium when the chromosomes carinatum, stained with are exposed to quinacrine (奎纳克林， ultraviolet light. 阿的平) to reveal Q band.
2018/11/16 Variation in Chromosome Number and Structure 7
The most popular of these uses Giemsa stain, a mixture of dyes named after its inventor, Gustav Giemsa.
2018/11/16 Variation in Chromosome Number and Structure 11
徐道觉 (Tao Chiuh Hsu, 1917-2003)
蒋有兴 (Joe Hin Tjio，1919-2001)
低渗法染色体分散技术发现者
浙江大学农学院毕业生、谈家 桢的学生、美籍华人
The distinction between aneuploidy and polyploidy is that aneuploidy refers to a numerical change in part of the genome, usually just a single chromosome, whereas polyploidy refers to a numerical change in a whole set of chromosomes. Aneuploidy implies a genetic imbalance, but polyploidy does not.
2018/11/16
Variation in Chromosome Number and Structure
2
Chapter Outline
Cytological Techniques
PBaidu Nhomakorabealyploidy (多倍体)
Aneuploidy (非整倍体)
Rearrangements of Chromosome Structure
2018/11/16
Variation in Chromosome Number and Structure
15
Organisms with complete, or normal, sets of chromosomes are said to be euploid (整倍体). Organisms that carry extra sets of chromosomes are said to be polyploid (多倍 体), and the level of polyploidy is described by referring to a basic chromosome number, usually denoted n. Thus, diploid, with two basic chromosomes sets, have 2n chromosomes; triploids, with three sets, have 3n; tetraploids, with four sets; have 4n; and so forth.
2018/11/16 Variation in Chromosome Number and Structure 9
Metaphase human chromosomes stained with acridine orange (吖啶橙) to show R banding. Metaphase chromosome of the Melipona rufiventris (卖 蜂), M. mondury and M. seminigra fuscopilosa stained to show C banding.