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