细胞分子生物学 第10章 基因与染色体的分子结构.ppt

10 MOLECULAR STRUCTURE OF GENES AND CHROMOSOMES 10.1 Molecular Definition of a Gene 10.2 Chromosomal Organization of Genes and Noncoding DNA 10.3 Mobile DNA 10.4 Structural Organization of Eukaryotic Chromosomes 10.5 Morphology and Functional Elements of Eukaryotic Chromosomes 10.6 Organelle DNAs 10.1 Molecular Definition of a Gene Comparison of simple and complex eukaryotic transcription units 10.2 Chromosomal Organization of Genes and Noncoding DNA gene family: A set of duplicated genes that encode proteins with similar but nonidentical amino acid sequences; Genomes of Many Organisms Contain Much Nonfunctional DNA(约1.5%的人类基因用于编码蛋白和功能性RNA) Protein-Coding Genes May Be Solitary or Belong to a Gene Family Tandemly Repeated Genes Encode rRNAs, tRNAs, and Histones(编码完全相同或几乎相同的蛋白或功能性RNA) Most Simple-Sequence DNAs Are Concentrated in Specific Chromosomal Locations(也称为卫星DNA，哺乳动物中，常常在着丝粒附近或端粒上) 10.3 Mobile DNA 中度重复DNA序列可以在基因组中运动转移，因此称为移动基因 移动基因的运动分为DNA和RNA介导两种方式 在原核和真核生物中都有NDA介导的移动基因 哺乳动物的移动基因分为2类：长散步元件(long interspersed elements LINEs) 和短散步元件(short interspersed elements SINEs)长散步元件分为L1,L2,L3三种； 10.4 Structural Organization of Eukaryotic Chromosomes 10.5 Morphology and Functional Elements of Eukaryotic Chromosomes Chromosome Number, Size, and Shape at Metaphase Are Species-Specific During Metaphase, Chromosomes Can Be Distinguished by Banding Patterns and Chromosome Painting Three Functional Elements Are Required for Replication and Stable Inheritance of Chromosomes(replication origins、centromere、telomeres) 10.6 Organelle DNAs 线粒体含有多样的线粒体DNA (mtDNA) mtDNA 是可遗传的，可编码 rRNAs、 tRNAs、和一些线粒体蛋白 在不同的有机体中，mtDNA的尺寸、和编码能力是可变的 线粒体基因的表达产物并不会输送出线粒体外 叶绿体DNA含有巨大的环状DNAs，能够编码数百种蛋白 * * * 基因：产生一条多肽链或功能性 RNA所必须的全部核苷酸序列 简单转录单元只编码一种蛋白 复杂转录单元可编码多种蛋白 Classification of mobile elements into two major classes The coding capacity of human mitochondrial DNA (mtDNA) ND:NADH-CoQ亚基编码基因； His：相应的tRNA基因； 哺乳动物mtDNA不含内含子 *