第10-1章微生物学(赵立平).pdfVIP

How can we change information encoded in a gene? Lecture 10-1 Bacterial Genetics I. Mutation and Recombination Chapter 11 in BROCK BIOLOGY OF MICROORGANISMS School of Life Science and Biotechnology, Shanghai Jiao Tong University I. Mutation and Recombination Shanghai Jiao Tong University 10.1 Mutations and Mutants Important concepts 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 Shanghai Jiao Tong Univerity Shanghai Jiao Tong University 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- Shanghai Jiao Tong Univerity Shanghai Jiao Tong University 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 Selectable mutants-drug resis