Microbial Genetics

• Mutation• Genetic

Recombination• Model organism

– E. coli

• Molecular Cloning• Bioinformatics

“Golden” Rice

Plasmid Types

• Resistance Plasmids – R Plasmids

• Virulence Plasmids• Bacteriocins• Engineered Plasmids

Mutants

• Mutation• Wild Type• Genotype• Phenotype

Isolation of Mutants

• Replica Plating• Auxotrophs –

Nutritional Mutants• Prototroph –

Wild Type

• Penicillin Selection Method – Kills Growing Cells

Mutations

• Spontaneous Mutations

• Point Mutations• Base-Pair

Substitution• Silent,• Missense, or• Nonsense Mutations

Conditional Lethal Mutations

• Temperature Sensitive Mutations

30 C 40 CIncubation Temperature

Reading Frame

Frame Shift

Mutation

• Back

Mutation

• Suppressor

Mutation

Mutation

Prototroph Auxotroph

Back Mutation

Mutation Back Mutation Normal Protein

Reversion

Other Mutations

• Deletions – Lose of a Piece of DNA

• Insertions – Additions of a Piece of DNA

• Translocation – Movement of a Piece of DNA to a New Location in the Genome

Inversion

Orientation of a Piece of DNA is Reversed in the Genome - Phase Variation

Mutation Rate

• Spontaneous (Natural or Background) Mutation Rate

• DNA ~ 1 per Million (varies between genes and location)

• RNA ~ 1 per Thousand

• Mutagens – Anything that Increases the Mutation Rate

Mutagens

• Chemicals • Base Analogs – Chemically Resemble Base

•

Intercalating Agent

Inserts Between Base Pairs

• Radiation

• UV Light

• Ionizing Radiation

• DNA Repair

• SOS Regulatory System

04/19/23 15

Biological Mutagens

• Transposons – Can Insert Into Gene

• Transposon Mutagenesis

• Site Directed Mutations – Man-made

Ames Test• Mutagens Carcinogens• Ames Test Measures Back Mutation Rates to

Detect Carcinogens• Liver extract

Bacterial Gene Transfer

• Genetic Recombination

• 3 Types of Bacterial Gene Exchange:

• 1. Transformation• “Naked DNA”• Competent

• Transfection in Eukaryotes

• Particle (Gene) Guns Insert DNA

•Electroporation

2. Transduction

• Generalized Transduction

• Specialized Transduction

• Lysogeny Can Lead to Phage Conversion

3. Conjugation

• Plasmids• Copy Number• Incompatibility• Curing• Conjugative Plasmid

Chromosomal Mobilization

• Fertility (F) Plasmid• Episome• HFr Strain• Sex Pili

Gene Maps

• Interrupted Matings

E. coli Chromosome• 4,639,221 Base

Pairs• 4,288 Open

Reading Frames• 88% ORF• 1% rRNA, tRNA• 10% Promoter,

Origin, etc• 6% Operons

Lateral Gene Transfer

• Horizontal Gene transfer

• Pathogenicity Islands

• ICE – Integrative and Conjugative Elements

Transposition

• Transposase

• Conservative Transposition

• Replicative Transposition

• Phase Variation

• Inversion

Genomics

• Mycoplasma genitalium Genome

• 470 Open Reading Frame

• Genomic Mining

Genetic Word List

Mutation

Genetic Recombination

Microbial Models

Molecular Cloning

Biotechnology

Mutants

Genotype – Phenotypes

Wild-Type

Isolation Mutants

Replica plating

Auxotroph – Prototroph

Penicillin-Selection Method

Spontaneous Mutations

Point Mutation

Base-Pair Substitution

Silent, Missense, Nonsense

Mutations

Genetic Word List 2

Temperature Sensitive Mutation

Reading Frame

Frame Shift Mutation

Back Mutations

Suppressor Mutation

Deletions

Insertions

Translocation

Inversion

Mutation Rate

DNA ~10-6 RNA ~10-3

Mutagens

Chemicals

Base Analogs

Intercalating Agents

Radiation

UV Light

Genetic Word List 3

Ionizing Radiation

DNA Repair

SOS Regulatory System

Biological Mutagens

Transposons

Site Directed Mutations

Carcinogenesis

Ames Test

Genetic Recombination

Bacterial Gene Transfer

Transformation

Competent

Transfection

Electroporation

Particle gun

Genetic Word List 4

Transduction

Generalized Transduction

Specialized Transduction

Lysogeny

Phage conversion

Conjugation

Plasmids

Copy Number

Incompatibility

Curing

Conjugative Plasmids

Resistance Plasmids

R Plasmids

Virulence Plasmids

Bacteriocin

Engineered plasmids

Genetic Word List 5Chromosomal Mobilization

Sex Pili

Fertility (F) Plasmids

HFr Strains Interrupted Matings

Genetic Maps

Transposition

Transposase

Conservative – Replicative Transposition

Phase Variation

Inversion

Escherichia coli Chromosome

4,639,221 Base Pairs

4,288 Open Reading Frames

Horizontal Gene Transfer

Genetic Word List 6

Pathogenicity Islands

Genomics

Mycoplasma genitalium

Genome

470 Open Reading Frames

Genomic Mining