CHAPTER 5The Genetics of Bacteria

and Their Viruses

CHAPTER 5The Genetics of Bacteria

and Their Viruses

Copyright 2008 © W H Freeman and Company

CHAPTER OUTLINE5.1 Working with microorganisms

5.2 Bacterial conjugation

5.3 Bacterial transformation

5.4 Bacteriophage genetics

5.5 Transduction

5.6 Physical maps and linkage maps compared

Working with microorganisms

Dividing bacterial cells

Chapter 3 Opener

The fruits of DNA technology, made possible by bacterial

genetics

Figure 5-1

Bacteria exchange DNA by several processes

Figure 5-2

Bacterial colonies, each derived from a single cell

Figure 5-3

Distinguishing lac+ and lac- by using a red dye

Figure 5-4

Table 5-1

Model Organism Escherichia coli

Model Organism E. Coli

Bacterial conjugation

Mixing bacterial genotypes produces rare recombinants

Figure 5-5a

Mixing bacterial genotypes produces rare recombinants

Figure 5-5b

No recombinants are produced without cell contact

Figure 5-6

Bacteria conjugate by using pili

Figure 5-7

F plasmids transfer during conjugation

Figure 5-8a

F plasmids transfer during conjugation

Figure 5-8b

Integration of the F plasmid creates an Hfr strain

Figure 5-9

Donor DNA is transferred as a single strand

Figure 5-10

Crossovers integrate parts of the transferred donor fragment

Figure 5-11

Tracking time of marker entry generates a chromosome map

Figure 5-12a

Tracking time of marker entry generates a chromosome map

Figure 5-12b

A single crossover inserts F at a specific locus, which thendetermines the order of gene transfer

Figure 5-13

The F integration site determines the order of gene transfer inHFRs

Figure 5-14

Two types of DNA transfer can take place during conjugation

Figure 5-15

A single crossover cannot produce a viable recombinant

Figure 5-16

Figure 5-17

The generation of various recombinants by crossing over indifferent regions

Figure 5-18

Faulty outlooping produces F´, an F plasmid that contains

chromosomal DNA

Table 5-2

A plasmid with segments from many former bacterial hosts

Figure 5-19

An R plasmid with resistance genes carried in a transposon

Figure 5-20

Bacterial transformation

Mechanism of DNA uptake by bacteria

Figure 5-21

Bacteriophage genetics

Structure and function of phage T4

Figure 5-22

Electron micrograph of phage T4

Figure 5-23

Electron micrograph of phage infection

Figure 5-24

Cycle of a phage that lyses the host cells

Figure 5-25

Figure 5-26

A plaque is a clear area in which all bacteria have been lysed by

phages

Figure 5-27

A phage cross made by doubly infecting the host cell withparental phages

Plaques from recombinant and parental phage progeny

Figure 5-28

Transduction

Figure 5-29

Generalized transduction by random incorporation of bacterial

DNA into phage heads

From high cotransduction frequencies, close linkage is inferred

Figure 5-30

Table 5-3

Transfer of prophage during conjugation can trigger lysis

Figure 5-31

Transfer of prophage during conjugation can trigger lysis

Figure 5-31a

Transfer of prophage during conjugation can trigger lysis

Figure 5-31b

phage inserts by a crossover at a specific site

Figure 5-32

Faulty outlooping produces phage containing bacterial DNA

Figure 5-33a

Faulty outlooping produces phage containing bacterial DNA

Figure 5-33b

Faulty outlooping produces phage containing bacterial DNA

Figure 5-33c

Physical maps and linkage maps compared

A map of the E. coli genome obtained genetically

Figure 5-34

Part of the physical map of the E. coli genome, obtained by

sequencing

Figure 5-35

Physical map of the E. coli genome

Figure 5-36

Proportions of the genetic and physical maps are similar but not

identical

Figure 5-37

Figure 5-38

Transposon mutagenesis can be used to map a mutation in the

genome sequence