Chapter 3 Animal Genomics,Chromosome
第三章 动物基因组:遗传的染色体基础
? A cell is a unit of structure and function细胞是生命
有机体基本的 结构单位 和 功能单位
? An animal cell consists of membrane,cytoplasms
and nucleus 动物细胞由 细胞膜, 细胞质 和 细胞核 三部
分构成
? The eukaryotic chromosome is a threadlike
nuclear structure consisting mainly of a complex
of DNA (the genetic material) and proteins真核生
物染色体是一种纤丝状核结构, 主要由 DNA复合体及蛋
白质构成
本章内容 Outline of the chapter
? The morphological and structural features of
chromosome染色体的形态与结构
? Chromosomal number染色体的数目
? Chromosomal behaviours染色体的行为
? Chromosomal theory of inheritance 遗传的染色体学

? Structural variations of chromosome染色体结构变异
? Variations of chromosome numbers 染色体数目变异
The morphological and structural
features of chromosome
染色体的形态与结构
? Chromosomes have key morphological and
molecular features such as centromere,
telomere,chromatid,and DNA sequences that
designate replication origin染色体具有诸如着丝
粒, 端粒, 染色单体和作为复制起源的 DNA序列等
形态和分子特征
The morphological features of chromosome
染色体的一般形态
? chromatids染色单体
? centromere着丝粒
? arms染色体臂
? primary constriction初级缢痕
? secondary constriction and nucleolar
organizer次级缢痕和核仁形成区
? satellite随体
chromatids染色单体
Centromere
着丝粒
(初级缢痕)
Arms
染色体臂
secondary constriction次级缢痕
Satellite
随体
Chromosomal structure
染色体的结构
? DNA 27%
? Protein 蛋白质 67%
? RNA 6%
Nuclesome
Chromosomal structure
染色体的四级结构
Homologous chromosomes and autosomes
同源染色体与常染色体
? Homologous chromosomes are those chromosomes
that occur in pairs and are generally similar
in size and shape,one having coming from the
male parent and other from the female parent二
倍体中染色体两两配对, 配对的染色体大小, 着丝粒
位臵都是一样的, 这样的染色体称为 同源染色体
? Chromosomes related to sex determination such
as X and Y are sex chromosomes and all the
other chromosomes in the genome are called
autosomes同源染色体中有一对与性别有关, 称为 性染
色体, 其它染色体称为 常染色体
Karyotype analysis染色体组型分析
? Karyotype,The chromosome constitution of a cell
or an individual; chromosomes arranged in order
of length and according to position of centromere
根据各个细胞中染色体的长度大小, 着丝粒的位臵和随
体的有无等因素把它们排列起来, 这就是 染色体组型
( 也叫核型 karyogram)
? Karyotype analysis chromosomes arranged in
order of length and according to position of
centromere染色体组型分析,把多对染色体配对再排列
起来进行研究
? Significance of Karyotype analysis染色体组型分析
的意义
Normal human
male karyotype
正常男性核型( G带)
Normal human
male karyotype
正常女性核型( G带)
C-banding C带显色
C-banding (C带 )
Normal human male karyotype
(silver NOR stain)银染显色 Ag-NOR
Normal human male
karyotype (silver NOR stain)
Human
idiogram
人的染色体
组型模式图
Chromosomal number
染色体的数目
? Chromosomal numbers are constant for each
species每一种生物的染色体数目均是恒定的
? Most of animal species are diploid and each
somatic cell consists of two sets of chromosomes
(2n)多数高等动物是二倍体, 即它们在每一体
细胞中有两组同样的染色体, 用 2n表示
? Each germ cell has a set of chromosomes,
named as haploid亲本的每一配子常有一组染
色体, 叫 单倍体, 用 n表示
The numbers vary tremendously among species and
have little relation to the complexity of the organism
Organism Chr,No,Organism Chr,No.
Yeast
Field horsetail
Bracken fern
Giant sequoia
Macaroni wheat
Bread wheat
Garden pea
Wall cress
Corn
Lily
32
216
116
22
28
42
14
10
20
12
Fruit fly
Nematode
House fly
Scorpion
Geometrid moth
Common toad
Chicken
Mouse
Gibbon
Human being
8
M11,F12
12
4
224
22
78
40
44
46
染色体的行为
Chromosomal
behaviours
The cell cycle of a
typical mammalian
cell
? Cell cycle,The cyclical events that occur during
the divisions of mitotic cells,细胞周期 — 指从一次有
丝分裂结束到下一次分裂结束之间的期限
? A typical cell cycle consists of interphase
and mitotic stage细胞周期由 间期 和 分裂期 组成
? Interphase 间期也叫静止期,可再细分为 G1期, S
期 和 G2期 三个阶段
Mitosis 细胞分裂 — 有丝分裂
?Prophase前期
?Metaphase中期
?Anaphase后期
?Telophase末期
Meiosis细胞分裂 — 减数分裂
? Meiosis I
?Prophase I 前期 I
– Leptotene细线期
– Zygotene偶线期
– Pachytene粗线期
– Diplotene双线期
– Diakinesis终变期或叫浓缩期
?Metaphase I 中期 I
?Anaphase I 后期 I
?Telophase I 末期 I
?Interphase 间期
? Meiosis II
? Prophase II 前期 II
? Metaphase II 中期 II
? Anaphase II 后期 II
? Telophase II 末期 II
Spermatogenesis
动物配子的形成 -精子形成
Oogenesis动物配子的形成 --卵子的形成
Chromosomal theory of inheritance
遗传的染色体学说
? Gene locates in the chromosome
基因是在染色体上
Chromosomes may differ
in size and in position of
the centromere
Structural variations of chromosome
染色体结构变异
Structural variations of chromosome are 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
染色体结构变异 是由于染色体断裂后或不接合或进行差错
的接合而产生的,会造成染色体上基因数目和基因位臵
的变化,导致细胞学行为和遗传效应的异常
Structural variations of chromosome
? deficiency缺失
? duplication重复
? inversion倒位
? translocation易位
deficiency缺失
? A chromosome with a deletion has genes
missing
? Deletions are generally harmful to the
organism
A B C
A B C D E F
A chromosome with a duplication has extra genes
重复 — 染色体多了一个额外的片段
顺接重复 -重复片段上基因排列顺序与
染色体的原基因排列顺序相同
反接重复 -重复片段上基因排列顺序与
染色体的原基因排列顺序相反
A B C D E F
A B C D E E D C F
A B C D E C D E F
重复的起因、细胞与遗传学效应
? 起因 --减数分裂时同源的非姐妹染色体之间发生
不等交换
? 细胞学效应 --同源染色体配对时出现弧形的结构
? 遗传学效应 --影响生活力,甚至引起个体死亡
? Deletions are usually more harmful than
duplications of comparable size
An increase in the number of copies
of a chromosome segment
A chromosome with an inversion has some
genes in reverse order
倒位指染色体片段断裂倒转方向重新接合起来
倒位片段在染色体一臂之内叫做 臂内倒位,
倒位片段涉及染色体两臂叫做 臂间倒位
倒位的起因、细胞与遗传学效应
? 起因 --染色体一片段断裂倒转方向重新接合起来
? 细胞学效应 --产生倒位环
? 遗传学效应 --倒位纯合体一般是正常的,可以正
常联会,产生正常的配子;如果倒位环内发生交
换,将会产生部分不育的配子
Result of pairing
and crossing-
over within an
inversion
Reciprocal translocations interchange
pairs between chromosomes
易位
染色体一个片段移到非同源的染色体上
叫做 简单易位,两条非同源染色体相互交
换染色体片段叫做 相互易位 。易位的一种
特殊形式叫 罗伯逊易位,是指两个近端着
丝粒的非同源染色体融合而成一条染色体
易位的细胞与遗传学效应
? 易位的细胞学效应 --出现具有特征性的
十字形图象
? 遗传学效应 --易位杂合体产生部分不育
配子
Translocation
Cancer is often associated with
chromosomal abnormalities
Variations of chromosome
numbers 染色体数目变异
? Euploid 倍数性变异
? Aneuploid 非倍数性变异
Euploid 倍数性变异
一个配子中所含的染色体构成一个
染色体组。体细胞中含有一个或若干个
染色体组的个体叫做 整倍体 (euploid),
含一个染色体组的叫 单倍体 (haploid),
含二个染色体组的叫 二倍体 (diploid),
含三个染色体组的叫 三倍体 (triploid)
染色体的倍数性变异 变异类型 染色体组成
单倍体
二倍体
三倍体
同源四倍体
异源四倍体
( A B C D )
( A B C D ) ( A B C D )
( A B C D ) ( A B C D ) ( A B C D )
( A B C D ) ( A B C D ) ( A B C D ) ( A B C D )
( A B C D ) ( A B C D ) ( A ` B ` C ` D ` ) ( A ` B ` C ` D ` )
非倍数性变异
在二倍体染色体数目基础上发生个别
染色体增加或减少的个体叫做非整倍体
( aneuploid) 。染色体数目的这种变异
叫做 非倍数性变异
染色体的非倍数性变异
变异类型 染色体组成
三 体
四 体
双三体
单 体
缺 体
( A B C D ) ( A B C D ) ( A )
( A B C D ) ( A B C D ) ( AA )
( A B C D ) ( A B C D ) ( AB )
( A B C D ) ( A B C )
( A B C ) ( A B C )
Aneuploid variations
Main points of this chapter (I)
? Chromosomes in eukaryotic cells are usually
present in pairs
? The chromosomes of each pair separate in
meiosis— one going to each gamete
? In meiosis,the chromosomes of different pairs
undergo independent assortment
? Chromosomes consist largely of DNA combined
with histone proteins
? In many animal,sex is determined by a special
pair of chromosomes— the X and Y
Main points of this chapter (II)
? Irregularities in the inheritance of the X-linked
gene in Drosophila gave experimental proof of
the chromosomal theory of heredity
? Duplication of the entire chromosome
complement in a species or in a hybrid between
species is a major process in the evolution of
higher plants
? The genetic unbalance caused by a single
chromosome that is extra or missing may have a
more serious phenotypic effect than an entire
extra set of chromosomes
Main points of this chapter (III)
? Chromosome abnormalities are an important
cause of human genetic disease and are a
major factor in spontaneous abortions
? Aneuploid chromosome rearrangements usually
have greater phenotypic effects than euploid
chromosome rearrangements
? Reciprocal translocations result in abnormal
gametes because they upset segregation
? Transposable elements are DNA sequences able
to change their location within a chromosome or
to move between chromosomes