Recombination in bacteria

transduction
transformation
conjugation

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. V irulent – 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.

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

9. 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.

10. Generalized Transduction

11. 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 .

12. 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.

13. 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,

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

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

16. What happen during conjugation

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

18. Hfr conjugation