This document discusses three types of genetic transfer in bacteria: transduction, conjugation, and transformation. It focuses on transduction, describing how bacteriophages can transfer genetic material from one bacteria to another. There are two types of transduction - generalized, where any bacterial gene can be transferred randomly, and specialized, where only certain genes are transferred. The document provides details on the lytic and lysogenic cycles of bacteriophages and how this relates to generalized and specialized transduction. It also briefly discusses conjugation, the transfer of genetic material between bacteria via direct contact through plasmids.

1. Recombination in bacteria
By.
Pandya Dilip
Cug/2014/1078

2. Gene transfer in becteria
• transfer genetic material from one becteria to
another becteria
• In bacteria genetic transfer can happen three
ways:
– Transduction
– Conjugation
– transformation

3. Transduction

4. Transduction
• Definition: gene transfer from a donor to a
recipient by way of a bacteriophage
• Discover by lederberg & zinder in 1951
• Bacteriophage (phage): A virus that infects
bcteria

5. Bacteriophage - structure

6. Types of Bacteriophage
• Bacteriophages have been classified into two types
on the basis of their interaction with a bactria cell.
1. Virulent phages.
2. Temperate phages.
• Virulent – always multiply & lyse the host cell after
infection.
• Temperate phage: That have a choice between two
life-style after infection.

7. 1.Lytic cycle
2.lysogenic cycle
• 1. Lytic cycle = they reproduce & lyse their
host cell just like virulent phages.
• Lysogenic cycle = their chromosome are
integrated in to the chromosome of the host.

9. Transduction
• Types of transduction
1. Generalized - Transduction in
which potentially any donor
bacterial gene can be transferred.
2. Specialized- Transduction in which
only certain donor genes can be
transferred

10. Generalized transduction
• Starts with the LYTIC CYCLE where a T- even
phage infects E. coli killing the host cell, and
synthesizing >100 copies of itself.
• The T-even phage randomly packages bacterial
DNA in a few defective phages.
• Once a T – even phage infects another E. coli, this
genetic information can be recombined into the
host cell without causing the lytic cycle.
• New genetic information is thereby transduced
from one bacteria to another.

11. Generalized Transduction

12. Specialized Transduction
• In specialized transducing particle carries only specific
portions of the bacterial genome.
• Specialized transduction by a temperate bacteriophages
which chromosome are able to integrate at a specific
attachment site on host chromosome.
• Phages chromosome & bacterial chromosome is a attach
specific attachment site by a covalently in prophages.
• The gal transducing phage (lambda) makes ~ 2,000 copies
of itself with the gal gene, and infects other E.coli.
• When gal integrates into the nucleoid of other E. coli, it
may provide these bacteria with a new capacity to
metabolize galactose.

15. • The best-studied example of specialized
transduction is the lambda phage. The lambda
genome inserts into the host chromosome at
specific locations known as attachment or att
sites.
• The phage att sites and bacterial att sites are
similar and can complex with each other.

17. conjugation
• Bacterial conjugation is the transfer of genetic
material (plasmid) between bacterial cells by
direct cell-to-cell contact or by a bridge-like
connection between two cells.
• Discovered in 1946 by Joshua Lederberg and
Edward Tatum,

18. BACTERIA A BACTERIA B
Transfer of genetic material from
bactria A to bacteria B by physical
contact is called conjugation.

19. Who is donor ?
F plasmid absent
donor recipient
F + F-Male
cell femal cell

21. What happen during conjugation

22. What is Hfr cell?
• When F factor/ plasmid exists in an
integrated state with the host
chromosome

23. Hfr conjugation