第一章 遗传的染色体学说 染色体是遗传物质的主要载体 I Evidence that genes reside in the nucleus 2 Evidence that genes reside in chromosomes 3染色体的概念( chromosome) 狭义的概念 广义的概念 chromatin chromosome 常染色质 (euchromatin)与异染色质( heterochromatin) constitutive heterochromatin facultative heterochromatin 4染色体的数目
第一章 遗传的染色体学说 一 染色体是遗传物质的主要载体 1 Evidence that genes reside in the nucleus 2 Evidence that genes reside in chromosomes 3 染色体的概念（chromosome) 狭义的概念 广义的概念 chromatin 与 chromosome 常染色质(euchromatin) 与 异染色质(heterochromatin) constitutive heterochromatin facultative heterochromatin 4 染色体的数目
物种 染色体数目 2n=46 人金黄马驴 丝猴 2n=44 牛 2n=60 2n=64 2n=62 小家鼠 2n=40 大家鼠 2n=42 果蝇 2n=8 洋葱 2n=16 玉米 2n=20 水稻 2n=24 豌豆 n=14 向日葵 2n=34 衣藻 2n=16
物种 染色体数目 人 2n=46 金丝猴 2n=44 黄牛 2n=60 马 2n=64 驴 2n=62 小家鼠 2n=40 大家鼠 2n=42 果蝇 2n=8 洋葱 2n=16 玉米 2n=20 水稻 2n=24 豌豆 2n=14 向日葵 2n=34 衣藻 2n=16
4染色体的一般形态结构
4 染色体的一般形态结构
2 3 14683 6 8 IO 12 日8 13 14 15 16 18 19 20 21 22 X Y Figure Karyotype of a human male
名称 两臂长度比(长/短)符号 中部着丝粒染色体 metacentric chro 1-1.7 M. m 近中着丝粒染色体 submetacentric chro 1.7-3 S 近端着丝粒染色体 acrocentric chro 3-7 st 顶端着丝粒染色体 telocentric chro t. t
名称 两臂长度比（长/短） 符号 中部着丝粒染色体 metacentric chro 1-1.7 M,m 近中着丝粒染色体 submetacentric chro 1.7-3 sm 近端着丝粒染色体 acrocentric chro 3-7 st 顶端着丝粒染色体 telocentric chro 7- t , T
5染色体的分子结构 化学组成:1/3DNA,1/3 Histones and 1/3 Nonhistone ()Nucleosomes H2B H4 H2A H3 Linker DNa Linker dna
5 染色体的分子结构 化学组成：1/3 DNA,1/3 Histones and 1/3Nonhistons (1)Nucleosomes
细胞类别 核小体DNA含量(bp) 曲霉 154 酵母 165 链孢霉 170 鼠骨髓 192 鼠肝 198 鼠肾 196 鸡输卵管 196 雏鸡红细胞 207 海胆精子 241 Hela(培养) 183
细胞类别 核小体DNA含量(bp) 曲霉 154 酵母 165 链孢霉 170 鼠骨髓 192 鼠 肝 198 鼠肾 196 鸡输卵管 196 雏鸡红细胞 207 海胆精子 241 Hela(培养) 183
Histones abound in the chromatin of all eukaryotic cells TABLE Some Molecular Characteristics of the histone Proteins Found in Calf Thymus* Histone Basic/Amino Acid Molecular Weight Total Amino Acid Residues H1 54 23.000 224 H2A 14 13960 H2B 1.7 13,774 125 H 1.8 15,273 H4 11.236 102 Note the small size of the histones; in addition, their predominantly basic amino aad constitution ensures that they will be positively charged in physiological conditions. Nonhistones proteins have diverse functions
Nonhistones proteins have diverse functions Histones abound in the chromatin of all eukaryotic cells
gure Nonhistone proteins have diverse functions (a)Some nonhistone proteins form the chromosome scaffold. when the human chromosome in this picture was gently treated with detergents to remove the histones and some of the nonhistone proteins, a dark scaffold composed of some d the remaining nonhistone proteins, and in the shape of the two sister chromatids became visible. Loops of DNA freed by the detergent treatment surround the scaffold. (b)Some nonhistone proteins power chromosome movements along the spindle during cell division this figure, chromosomes are stained in blue and a nonhistone protein knowvn as CENP-E is stained in recl. CENP-E is located at the sister kinetochores of each duplicated chromosome and appears to play a major role in moving separated sister chromatics toward the spindle poles during anaphase