The Genetics of The Genetics of BacteriaBacteria

o`Circular DNACircular DNA - double stranded aka. its chromosome in nucleoid

Bacterial Bacterial Genome:Genome:

o PlasmidPlasmid - small circles of “extra” DNA - not necessary for survival, however -

important traitsfertility factor, antibiotic resistance

Bacterial chromo. replicatesBacterial chromo. replicates

-two copies move apart-cell grows

-plasma membrane pinches

-new cell wall deposited

division produces CLONE

Origin of Replication

Replication in both directions

Replication Forks move bidirectionly until they meet

Genetically identical daughter cells (clones)

mutations produce mutations produce genetic variation genetic variation

rapidly b/c rapidly b/c generational time is generational time is

sooooooo fastsooooooo fast

Genetic Genetic Recombination:Recombination:Mutants -

no growth - cannot synthesis required amino acid

Genetic Genetic Recombination:Recombination:

Combine

growth

Genetic Genetic Recombination:Recombination:

o`TransformationTransformation - uptake of “naked” DNA from the environmento TransductionTransduction -

o ConjugationConjugation -

Genetic Genetic Recombination:Recombination:

o`TransformationTransformation - uptake of “naked” DNA from the environment into its chromosome.

Genetic Genetic Recombination:Recombination:

o`TransformationTransformation

Genetic Genetic Recombination:Recombination:

o`TransductionTransduction -A phage (virus) transfers bacterial genes from one host cell to another.

Genetic Genetic Recombination:Recombination:

o`TransductionTransduction -A phage (virus) transfers bacterial genes from one host cell to another.

Genetic Genetic Recombination:Recombination:

o`TransductionTransduction -A phage (virus) transfers bacterial genes from one host cell to another.

Genetic Genetic Recombination:Recombination:

o`TransductionTransduction -A phage (virus) transfers bacterial genes from one host cell to another.

Genetic Genetic Recombination:Recombination:

o`ConjugationConjugation - bacterial cells join and transfer genetic material through a sex pilli.

F factor = fertility factor

F+

HFR

Genetic Genetic Recombination:Recombination:

o`ConjugationConjugation - bacterial cells join and transfer genetic material through a sex pilli.

R plasmid = resistance plasmid

“moveable genetic elements”

portions change locations within the chromosome, or they may copy into a new location.

GENETIC RESHUFFLING

1983 Nobel prize winner

Transposons - Example

Bacterial Genetic Recombinations

1. Transformation2. Transduction3. Conjugation4. Plasmids5. Transposons

Be able to discuss a few of these methods.