Bacteria Genetics Bacteria Genetics

Introduction Chromosome (bacteria are haploid; in other words, they have a single chromosome) Chromosome (bacteria are haploid; in other words, they have a single chromosome) Mutations (change in the base sequence of DNA) Mutations (change in the base sequence of DNA) Extrachromosomal genetic material Extrachromosomal genetic material Plasmid Plasmid Transposons Transposons Genetic recombination : Transfer of DNA from one bacterium to another Genetic recombination : Transfer of DNA from one bacterium to another

Introduction Changes in the genome can occur by two processes Changes in the genome can occur by two processes Mutations Mutations Genetic recombination Genetic recombination The changes in the genome is of considerable importance in terms of bacterial virulence and drug resistance The changes in the genome is of considerable importance in terms of bacterial virulence and drug resistance

Genetic Recombination The transfer of DNA from one organism to another with subsequent integration into the DNA of the recipient

Genetic Recombination Three mechanisms Three mechanisms Transformation Transformation Transduction Transduction Conjugation Conjugation

Transformation Definition Genetic recombination in which a DNA fragment from a dead degraded bacterium enter a competent recipient bacterium and is exchanged for a piece of DNA of the recipient Genetic recombination in which a DNA fragment from a dead degraded bacterium enter a competent recipient bacterium and is exchanged for a piece of DNA of the recipientMechanism Dead/donor bacterium – source of DNA Dead/donor bacterium – source of DNA DNA fragment from the dead donor bacterium binds to DNA binding protein on the cell wall of the competent living recipient bacterium DNA fragment from the dead donor bacterium binds to DNA binding protein on the cell wall of the competent living recipient bacterium

Transformation

Transduction Definitions Transduction - Genetic recombination in which a DNA fragment is transferred from one bacterium to another by a bacteriophage Transduction - Genetic recombination in which a DNA fragment is transferred from one bacterium to another by a bacteriophage Bacteriophage - A virus that only infects bacteria Bacteriophage - A virus that only infects bacteria horiz gene transfer-, Transposons--robert

Transduction

Conjugation Genetic recombination in which there is a transfer of DNA from a living donor bacterium to a recipient bacterium, often thorugh a sex pilus. Genetic recombination in which there is a transfer of DNA from a living donor bacterium to a recipient bacterium, often thorugh a sex pilus. Pilus - A tubular protein structure extending from a bacterial surface used for attachment to environmental surfaces or cells. A sex pilus is involved in bacterial conjugation. Pilus - A tubular protein structure extending from a bacterial surface used for attachment to environmental surfaces or cells. A sex pilus is involved in bacterial conjugation.

Plasmid Conjugation Plasmid Conjugation

R Plasmid Conjugation