1. The Genetics of Bacteria

2. Bacterial Chromosome
Circular, double-stranded DNA molecule tightly condensed into a structure called a nucleoid, which has no nuclear membrane
Bacteria replicate their DNA in both directions from a single point of origin
This is called theta replication, since the process resembles the Greek letter Θ

3. Bacterial Reproduction
Binary fission
Asexual
Results in a population with identical genes
Mutations DO occur spontaneously
Mutations are rare, and 1 in 1,000 can significantly change the population as a whole
Conjugation
Primitive sexual method
Transfer of genetic material between bacteria by direct cell-to-cell contact

4. Bacterial Transformation
Discovered by Frederick Griffith after using Diplococcus pneuomoniae
Can be natural or artificial
Provides a mechanism for recombination of genetic information in some bacteria

5. Bacterial Transformation
Small pieces of extracellular DNA are taken up by a living bacterium, leading to a stable change in the recipient cell
Common for people with insulin deficiencies (diabetes)

7. Plasmid
A foreign, small, circular, self-replicating DNA molecule that inhabits a bacterium
Bacteria can harbor many plasmids and will express the genes carried by the plasmid
The first plasmid discovered was the F plasmid, in which F stands for fertility

8. F Plasmid Bacteria that do not contain the F plasmid are called F-
Bacteria that contain the F plasmid are called F+
Bacteria that do not contain the F plasmid are called F-
The F plasmid contains genes that produce pili, cytoplasmic bridges that connect to an adjacent cell and that allow DNA to move from one cell to another in a form of primitive sexual reproduction called conjugation

9. R Plasmid
Makes the cell in which it is carried resistant to specific antibiotics
Can be transferred to other bacteria by conjugation
Bacteria with the R plasmid have a distinct evolutionary advantage over bacteria that are not resistant to antibiotics
This is happening today, particularly with tuberculosis