The document provides an overview of bacterial genetics, focusing on plasmids, transposons, and genetic variation. It covers key concepts such as DNA structure, types of plasmids, gene transfer methods including conjugation, transduction, and transformation, as well as bacterial mutations. The session aims to educate on genetic material, variation, and the mechanisms through which bacteria adapt and acquire new traits.

1. Bacterial genetic
Almugadam B Saad
Lecturer of medical microbiology
Faculty of medical laboratory sciences
Full name
Babiker Saad Almugadam Yousif
Faculty of medical laboratory sciences
University of El Imam El Mahadi
Kosti-Sudan
MSc University of Khartoum
BSc University of El Imam El Mahadi
Babiker Saad Almugadam Yousif

2. Bacterial genetic
- Definition
- Plasmids
- Transposons
Learning
objectives
By the end of this session , you
should the following :
- Transposons
- Programmed rearrangement
- Bacterial genetic variation
-Transfer of bacterial genes
- Recombination
- Bacterial mutation

3. Definitions
- DNA: Genetic material of cellular organism
- Gene : piece (segment) on chromosome or DNA , carry
information for specific character or structure.
- Genome : Total number of gene , include bacterial chromosome
and plasmid .
- Bacterial chromosome (Nucleiod): DS circular DNA , wound on
it self to form the nuclear mass
- Haploid: Has single chromosome , there for single copy of each
gene
- Diploid: Has a pair of each chromosome , there for single copy
of each gene

4. Bacterial Plasmids
- Extrachromosomal DS circular DNA , replicate autonomously .
- Types:
1- Conjugative (Transmissible =Transfer) plasmid
2- Non conjugative (Non transfer) plasmid
- Bacterial properties carry in plasmid :
1- Drug resistant (R factor plasmid)
2- Virulence : as neurotoxin produce by C.tetani , and colsin
produce by E.coli
3- Resistant to UV light
4- Bacteriophage resistant : encode resitriction endonuclease
5- Production of antimicrobial agent : antibiotics produce by
streptomyces

5. Transposons
- Piece of DNA which not capable of autonomous replication
(replicate as part of recipient DNA) but can move readly from one
side to anther either with in or between the DNA of bacteria or
plasmid or bacteriophage , also known as jumping gene.
-Types :
1- Replicative1- Replicative
2- Non replicative
- Properties carry in Jumping gene :
Carry antibiotics resistant gene

6. Programmed rearrangement
- Rearrangement of gene , through move of it from inactive
(storage) site to active site where express.
- Purpose :
1- To evade immune system

7. Bacterial genetic variation
-Mean change in bacterial gene which lead to loss of known
character or gain of new character.
- Types :
1- Phenotypic variation 2- Genotypic variation
- Phenotypic variation :
Change in bacterial character under influence of environmentChange in bacterial character under influence of environment
with out underline genetic change , not heritable , reversible.
Example : change spore formation
- Genotypic variation :
Heritable , irreversible change in bacterial character due to
change in genetic constitution.
Causes : 1- Mutation 2- Gene transfer

8. Transfer of bacterial genes
- Bacteria transfer gene to acquire a new character , to be more
pathogenic or resistant and to seek survival.
- Way of gene transfer :
1- Conjugation 2- Transduction 3- Transformation
- Conjugation :
Plasmid transfer from one bacteria to another via special type ofPlasmid transfer from one bacteria to another via special type of
pili (Sex = F pili) , occur only on prokaryotes.
- Transduction :
transfer of DNA from one bacteria to another via bacteriophage .
Classify to 2 types according to nature of transferred DNA.
Generalized transduction : any gene
Specialized transduction : only certain gene

9. -Transformation :
Transfer of DNA from one bacteria to another as naked DNA .Occur
when 2 cell in same fluid environment , recipient cell take the soluble
released DNA from donor cell.

10. Recombination
- means integration of transferred DNA into host cell chromosome
- Types :
1- Homologus : when 2 piece has extensive homologus region ,
pair up and exchange piece by process of breakage and reunion
2- Non homologus : in which little or non homology necessary

11. Bacterial mutation
- Mutation is permanent genetic variation , means change in the
sequence of bases in the DNA.
- Causes :
1- Spontaneous 2- Physical agent 3- Chemical agent
4- Radiation : Ionized radiation (X ray and Gamma ray)
- Types : Non ionized radiation (UV light)- Types : Non ionized radiation (UV light)
A- according to cause :
1- induced 2- Spontaneous
B- according to mechanism:
1- Base substitution : as result of base substitution
Their outcome either silent mutation or nonsense mutation or
miss-sense mutation.
2- Frameshift mutation : as result of insertion or deletion