tailieunhanh - Lecture Biochemistry (2/e): Chapter 29 - Reginald Garrett, Charles Grisham

DNA is the physical repository of genetic information in the cell and the material of heredity that is passed on to progeny. In this chapter, the following content will be discussed: How is this genetic information in the form of DNA replicated, how is the information rearranged, and how is its integrity maintained in the face of damage? | CHAPTER 29 DNA: Genetic Information, Recombination, and Mutation to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline DNA Carries Genetic Information Genetic Information in Bacteria Molecular Mechanism of Recombination The Immunoglobulin Genes Molecular Nature of Mutation RNA as Genetic Material Transgenic Animals The Transforming Principle is DNA Griffith in 1928 injected bacteria into mice Combination of heat-killed type S and non-virulent type R killed the mice Showed that type S had been transformed by the type R! In 1944, Oswald Avery showed that the active transforming agent was DNA! Further Proof In 1952, Hershey and Chase, studying bacteriophages, labelled DNA with 32P and protein with 35S Bacteriophage progeny produced by infection of bacteria contained 32P (thus DNA from the original phage), but not 35S (from the protein)! Genetic Information Can Be Transferred Between Bacteria In 1946, Lederberg and Tatum showed that two different strains of bacteria with different growth requirements could exchange genes Lederberg and Tatum surmised that the bacterial cells must interact with each other - the process is now known as sexual conjugation Chromosome Mapping by Interrupted Mating Passage of the ‘F factor’ from Hfr cells to F- cells also brings adjacent genes Genes from the Hfr chromosome are transferred in a fixed order This order can be mapped by ‘interrupted mating’ methods The genetic map obtained reveals a circular arrangement of genes Mechanism of Recombination General recombination: any pair of homologous DNA segments as substrates In 1964, Robin Holliday proposed a model involving single-stranded nicks at homologous sites Duplex unwinding, strand invasion and ligation create a Holliday . | CHAPTER 29 DNA: Genetic Information, Recombination, and Mutation to accompany Biochemistry, 2/e by Reginald Garrett and Charles Grisham All rights reserved. Requests for permission to make copies of any part of the work should be mailed to: Permissions Department, Harcourt Brace & Company, 6277 Sea Harbor Drive, Orlando, Florida 32887-6777 Outline DNA Carries Genetic Information Genetic Information in Bacteria Molecular Mechanism of Recombination The Immunoglobulin Genes Molecular Nature of Mutation RNA as Genetic Material Transgenic Animals The Transforming Principle is DNA Griffith in 1928 injected bacteria into mice Combination of heat-killed type S and non-virulent type R killed the mice Showed that type S had been transformed by the type R! In 1944, Oswald Avery showed that the active transforming agent was DNA! Further Proof In 1952, Hershey and Chase, studying bacteriophages, labelled DNA with 32P and protein with 35S Bacteriophage progeny .