��������������
UAA����� �!��UAG�����(��!��UGA�������
Bernstein(� ��"��!
���������������
1
T4 �������
2T4 ���������169K��
Photograph of phage T2 plaques on a lawn of E. coli
bacteria
T2 phage
T2 mutant phage
T2 r : rapid-lysis mutantT2 r+:wild-type
���� ����������� ���������������
3
Phage recombination in cells infected with two different strains of phage T2
19454���/,2.�#'����(��'��
��B�$5/3�'���#012-+�)"*!$#�h+r+, hr, hr+, h+r+��
T2h:���T2���# %���B/2&� # *���
T2 r : rapid-lysis ���
4
The life cycle of a lysogenic bacterial virus
������⇨λ���⇨ ���� 5λ����������48K��
Insertion of the chromosome of phage
λ into E.colichromosome
6
Insertion of Mu DNA
Mu��#�������������!"�����
7Mu����� �#�# ���
Transduction, the passive transfer of genetic material from one bacterium to another by means of carrier
phage particles
������
P1 ��������� 8P1������� ��93Kbp 2.2�
Specialized transducing phage
������
9
The demonstration of crossing over with
in the gene
10
The genetic map of the rIIA and rIIB genes of phage T4
��"����'��%� �� ��!#���%������(�$�&��!�����%� ������S. Benzer, PNAS, (1961)
11
Deletion mutations with in the rII region of T4
12
The rII region consists of two
distinct genes that can complement each other during
simultaneous infection
�������-���������
13
The Genetic Systems Provided by E. coli
Molecular Biology of the Gene
14
Fluctuation analysis of bacterial resistance to phage
�������� �����������
(�����)
15
Replica plating
�� � ������ �
16
Isolation of mutant E. coli cells with a specific growth
factor requirement
(!#""�)
���������� ��������
����� (auxotroph)���� (prototroph)
17���
Enriching mutants I
direct selection counterselection
18����
Enriching mutants II
physical selection
pH-sensitive dyes to detect metabolic mutants
Brute force isolation������ ���������������������
19
The use of growth factor requirments to demonstrate sexuality in E. coli
J. Lederberg & Tatum (1946)��������������������� ���
��
20
The attachment of a male F pilus to
the surface of a femail cell
F pilus
Type-I pili
21
���DsRed Ex- press �����Alexa-488 �����R17���������� 22
�� �������
���
23
The genetic map of F factor of E. coli
(94 kb)fin : fertility inhibitionphi : phage inhibition
inc : incompatibilityrep : replicationtra : the transfer of the F factor to female cells ilz : immunity to lethal zygosisori : origin of transer replication
Hfr : the positions where insertion elements on F recombine with the bacterial chromosome
24
The transfer of F+ DNAto an F- cell ����
25
Hfr (high frequency of recombination)
Integratiion of the F factor into the main chromosome
Movement of the bacterial chromosome from an Hfr cell into an F- cell
26
Conjugation between F- and Hfr bacteria, as shown in a classic diagram
F. Jacob & E.L. Wollman, Sexality and the Genetics of Bacteria, (1961)
27
The frequency fo donor Hfr marker genesThe relative gene order ⇨ azi-T1-lac-gal
28
Order of genes in conjugal transfer in different Hfr strains
29
Complete genetic map of E. coli I
Flagellar region I
Flagellar region IIIFlagellar region II
30
gal
lacazileuthr
Complete genetic map of E. coli II
31
The genetic maps
������
32
4.6Mb 4.2Mb
��
F<>I,��&7�2�F<>I0�:�8+#87-�!63&�
INAGJCAL��0*�+��'4�=KELAGJCAL)+�1$-OM�1NTs��)+/;1$-O M�2NE@DH?F<LB,$851��"��0�98("�. %+/1ONM�3N
IIN���1��� �2.14 0�58(1!OM�4N