BIOL 2051 Lecture Notes - Lecture 9: Horizontal Gene Transfer, Extrachromosomal Dna, Antimicrobial Resistance
Document Summary
Horizontal gene transfer: transformation, conjugation, transduction. Spreads useful genes among bacteria: antibiotic-resistance genes. Encode genes for cell to act as pathogen. Difference between typical e. coli in gut and pathogenic e. coli o157:h7: genes to degrade special metabolites (oil spills) Competent cell picks up free dna from the environment. Some cells can be made competent: salt treatments, electroporation- electrical shock opens pores in cell membrane, dna enters through pores. If free dna isn"t incorporated into chromosome, it will be degraded; free dna can"t replicate on its own. Bacterial dna is transferred from one bacterium to another by a virus. Dna is packaged into viral capsid: normally viral dna is packaged, rarely, bacterial dna is packaged by mistake. Can bring new bacterial genes to host. Generalized transduction- during viral infection, random pieces of bacterial dna are accidentally packaged into viral capsid; any part of the host chromosome can be transferred to a recipient.
