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The Genetics of Bacteria

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Presentation on theme: "The Genetics of Bacteria"— Presentation transcript:

1 The Genetics of Bacteria

2 Bacterial Genome: `Circular DNA - double stranded aka. its chromosome in nucleoid Plasmid - small circles of “extra” DNA - not necessary for survival, however important traits fertility factor, antibiotic resistance

3

4 REPLICATION

5 Bacterial chromo. replicates
-two copies move apart -cell grows -plasma membrane pinches -new cell wall deposited

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7 Origin of Replication

8 Replication in both directions

9 Replication Forks move bidirectionly until they meet

10 Genetically identical daughter cells (clones)

11 mutations produce genetic variation rapidly b/c generational time is sooooooo fast

12 no growth - cannot synthesis required amino acid
Genetic Recombination: Mutants - no growth - cannot synthesis required amino acid

13 Genetic Recombination:
Combine growth

14 Genetic Recombination:
`Transformation - uptake of “naked” DNA from the environment Transduction - Conjugation -

15 Genetic Recombination:
`Transformation - uptake of “naked” DNA from the environment into its chromosome.

16 Genetic Recombination:
`Transformation

17 Genetic Recombination:
`Transduction - A phage (virus) transfers bacterial genes from one host cell to another.

18 Genetic Recombination:
`Transduction - A phage (virus) transfers bacterial genes from one host cell to another.

19 Genetic Recombination:
`Transduction - A phage (virus) transfers bacterial genes from one host cell to another.

20 Genetic Recombination:
`Transduction - A phage (virus) transfers bacterial genes from one host cell to another.

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23 Genetic Recombination:
`Conjugation - bacterial cells join and transfer genetic material through a sex pilli. F factor = fertility factor

24 F+ HFR

25 Genetic Recombination:
`Conjugation - bacterial cells join and transfer genetic material through a sex pilli. R plasmid = resistance plasmid

26 transposons “moveable genetic elements”

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

28 transposons GENETIC RESHUFFLING

29 transposons 1983 Nobel prize winner

30 Transposons - Example

31 Bacterial Genetic Recombinations
1. Transformation 2. Transduction 3. Conjugation 4. Plasmids 5. Transposons Be able to discuss a few of these methods.


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