1. Bacterial and viral genetic systems

2. MEDIUM
CARBON SOURCE
P and N
Vitamins

3. PROTOTROPHES: minimal media
AUXOTROPHES (mutants): complete media

7. Conjugation

9. Gene transfer

13. Circular episome (F Factor) of E.Coli

14. Conjugation

22. Transformation

23. Transformation

24. Transduction

27. General Transduction:
Any gene can be tranferred from bacteria to bacteria
Specialized Transduction:
Only some genes can be transferred.

28. General Transduction
P1 phage of E. coli

29. thr
leu
azi
Selected
marker
Non selected
marker
Leu+ azi r =50%
thr+ =2%
thr+ azi r =0%
leu+ =3%
# transducing phages
For both markers
#total transducing phages
X 100% = gene linkage

30. Specialized transduction

33. Mapping of genes in phages
h+(infects onlyE.coliB); r- (big plaque with sharp edge)
h- (infects B andB/2); r+ (small plaque with fuzzy edge)
T2 phage

35. Phage T4 E.coliB E.coli B K12(l)
T4 with mutations in rII:
Host and plaque morphology
* r+ infects E.Coli B AND K12 (l) small plaque fuzzy edges;
* rII infects only E.Coli B big plaque sharp edge.
E.coli B
K12(l)