1. Batterjee Medical College

2. Ass. Prof. Dr. Manal El Said Department Head of Microbiology Bacteria Genetics

3. Batterjee Medical College Bacteria Genetics Bacteria have only one copy of their genome DNA, i.e., they are haploid. Eukaryotic cells have two copies of their genome DNA, i.e., they are diploid. Bacterial DNA is circular; human nuclear DNA is linear.

4. Batterjee Medical College Transfer of DNA Within Bacterial Cells Transposons Transposons are small pieces of DNA that move readily from one site on bacterial chromosome to another or from bacterial chromosome to plasmid. They carry antibiotic resistance genes. Transfer of transposons on plasmids to other bacteria by conjugation contributes to antibiotic resistance.

5. Batterjee Medical College Programmed rearrangements: are movement of genes from inactive ( storage) sites into active sites where they are expressed as new proteins. Bacteria can acquire new proteins (antigens) on their surface and evade the immune system e.g. Neisseria gonorrhoeae & Trypanosoma brucei Transfer of DNA Within Bacterial Cells

6. Batterjee Medical College The transfer of genetic information from one cell to another can occur by Transfer of DNA between Bacterial Cells Transformation Conjugation Transduction

7. Batterjee Medical College Transfer of DNA between Bacterial Cells: Conjugation Conjugation: DNA (plasmid carrying antibiotic resistance gene or chromosomal) is transferred from one bacterium to another. Donor bacterium have "fertility" plasmid (F plasmid). Pilin protein forms sex pilus (conjugation tube). DNA transferred by conjugation to recipient bacterium is a new copy that allows donor to keep a copy of DNA.

8. Batterjee Medical College It is process by which DNA (plasmid or chromosomal) is transferred from one bacterium to another by virus. Transferred DNA integrates into chromosomal DNA of recipient & new proteins, such as exotoxins, are made- a process called lysogenic conversion. Transfer of DNA between Bacterial Cells: Transduction

9. Batterjee Medical College Transfer of DNA between Bacterial Cells: Transformation Transformation is the process by which DNA itself, either DNA released from dying cells or DNA purified in the laboratory, enters a recipient bacterium.

10. Batterjee Medical College Transfer of DNA between Bacterial Cells Transfer Procedure Process Type of Cells Involved Nature of DNA Transferred Conjugation DNA transferred from one bacterium to another Prokaryotic - Chromosomal - plasmid Transduction DNA transferred by virus from one cell to another Prokaryotic -Generalized transduction: Any gene -Specialized transduction: Only certain genes TransformationPurified DNA taken up by a cell -Prokaryotic -Eukaryotic Any DNA Comparison of Conjugation, Transduction & Transformation