上泽充通大￥ Shanghai Jiao Tong University 1896 1920 1987 2006 How can we change information encoded in a gene? Lecture 10-1 Bacterial Genetics I.Mutation and Recombination Chapter 1o in 8 BROCK BIOLOGY OF MICROORGANISMS AI JIAO TONG UNI Chen Feng School of Life Science and Biotechnology, Shanghai Jiao Tong University http://micro.sjtu.edu.cn
1896 1920 1987 2006 Lecture 10-1 Bacterial Genetics I. Mutation and Recombination How can we change information encoded in a gene? Chapter 10 in BROCK BIOLOGY OF MICROORGANISMS Chen Feng School of Life Science and Biotechnology, Shanghai Jiao Tong University http://micro.sjtu.edu.cn
I.Mutation and Recombination 10.1 Mutations and Mutants Important concepts 圈Mutation变异突变 A heritable change in the base sequence of the genome of an organism @Mutantz变异株/型 A strain carrying such a heritable change @Wildtype野生型 A strain isolated from nature @Genotype基因型 A precise description of the genes an organism has @Phenotype表现型 The observable properties of an organism Chen Feng,Shanghai Jiao Tong Univerity
Chen Feng, Shanghai Jiao Tong Univerity 10.1 Mutations and Mutants Mutation变异/突变 • A heritable change in the base sequence of the genome of an organism Mutant变异株/型 • A strain carrying such a heritable change Wildtype野生型 • A strain isolated from nature Genotype基因型 • A precise description of the genes an organism has Phenotype表现型 • The observable properties of an organism Important concepts I. Mutation and Recombination
Designations in microbial genetics遗传学表示方式 Genotype Three lowercase letters followed by a capital letter (all in italics) ·hisc ©Gene's product A capital letter followed by two lowercase letters and then a capital letter ·HisC,RecA @ Phenotype A capital letter followed by two lowercase letters,with either a plus or minus superscript to indicate the presence or absence of that property ·Hist,His ·Amp,Amp Chen Feng,Shanghai Jiao Tong Univerity
Chen Feng, Shanghai Jiao Tong Univerity Designations in microbial genetics 遗传学表示方式 Genotype • Three lowercase letters followed by a capital letter (all in italics) • hisC Gene’s product • A capital letter followed by two lowercase letters and then a capital letter • HisC, RecA Phenotype • A capital letter followed by two lowercase letters, with either a plus or minus superscript to indicate the presence or absence of that property • His+ , His- • Ampr , Amps
10.1.1 Isolation of mutants:Screening Versus Selection 突变株的分离 圈Nonselectable mutants-pigment mutation非选择性变异株 mutants with no advantage or disadvantage over parental cells when growing under artificial conditions. The only way to find a nonselectable mutant is to screen a large population of the bacterium筛选 Selectable mutants-drug resistance mutation选择性变异株 mutants with an advantage under certain environmental conditions, so the progeny of the mutant cell are able to outgrow and replace the parent cells Chen Feng,Shanghai Jiao Tong Univerity
Chen Feng, Shanghai Jiao Tong Univerity 10.1.1 Isolation of mutants: Screening Versus Selection 突变株的分离 Nonselectable mutants-pigment mutation非选择性变异株 • mutants with no advantage or disadvantage over parental cells when growing under artificial conditions. • The only way to find a nonselectable mutant is to screen a large population of the bacterium筛选 Selectable mutants-drug resistance mutation选择性变异株 • mutants with an advantage under certain environmental conditions, • so the progeny of the mutant cell are able to outgrow and replace the parent cells
Nonselectable Mutant Example非选择性突变株 (b) 2012 Pearson Education.Inc. Pigmented mutants and nonpigmented mutants of Aspergillus.The wildtype has a green pigment.The white mutants make no pigment, whereas the yellow mutants cannot convert the pigment to the normal color
Chen Feng, Shanghai Jiao Tong Univerity Nonselectable Mutant Example非选择性突变株 Pigmented mutants and nonpigmented mutants of Aspergillus. The wildtype has a green pigment. The white mutants make no pigment, whereas the yellow mutants cannot convert the pigment to the normal color