Lecture 11 - Genetic Recombination

Genetic recombination is the transfer of new DNA from one organism to another.


 * Eukaryotes have sexual reproduction, and involves and alternation between generations. Eukaryotes have a vertical transfer of genes.


 * Prokaryotes do not perform sexual reproduction, but they do perform recombination. This type of transfer of genes is referred to as horizontal. No offspring are produced, but new genes are assimilated into the existing genome.

Conjugation
Genetic recombination involving pili, where both bacteria are alive. There are three mating species of bacteria: F+, F-, and HFR.

F+ is a donor, and has its genome. Has a plasmid called the F Particle or Fertility Factor, which codes for its own reproduction, pilus formation, and surfafce component that reduces the negative charge of the surface, to attract the negative charge of the F-.

F- is a recipient and lacks the fertility factor. It cannot produce pili and has a more negative charge than F+.

HFR is a donor whose Fertility Factor is incorporated into the genome. The incorporated Fertility Factor is also reffered to as an episome.

During conjugation between F+ and F-, the F+ makes the pilus and transfers its Fertility Factor to the F-, turning it into and F+. Recombination as a result of this process relatively rare (1 in 100,000)

High frequency recombination (HFR) recombines about once in every 100 interactions.

Plasmid Mediated Resistance

A bacteria  can have multiple plasmids as a result of conjugation.

Beta-Lactamase: Enzymes that break down antibiotics