1 / 16

Bacterial Genetics Workshop: Understanding Horizontal Gene Transfer

Join us today at noon for a seminar on bacterial genetics. Lab notebooks are due by 5 PM. Ch.8 Part 2 homework is due Wednesday. Learn about inducing genetic change in bacteria through mutations, horizontal gene transfer, and more mechanisms. Discover how DNA is passed onto daughter cells and the process of transformation, transduction, and conjugation. Explore the role of plasmids in genetic transfer. Engage in a hands-on activity simulating bacterial conjugation.

catrin
Download Presentation

Bacterial Genetics Workshop: Understanding Horizontal Gene Transfer

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Announcements • Seminar today at noon • Lab notebooks are due today by 5 PM • Ch. 8 Part 2 Homework due Wednesday • Review Session for Test 2? • Monday March 3rd • Tuesday March4th

  2. Bacterial Genetics Ch. 8 Part 2

  3. Question (2 Mins) What is one way to induce genetic change in bacteria? Answer: Mutations

  4. Horizontal Gene Transfer • Another method for genetic change in bacteria • The acquisition of genes from other cells • 3 mechanisms • DNA-mediated transformation • Transduction • Conjugation

  5. How does newly acquired DNA get passed onto daughter cells?

  6. DNA Must Have An Ori Or Undergo Homologous Recombination To Pass DNA To Daughter Cells • What DNA have an ori (origin of replication)? • Plasmids • Chromosomes • Parts of chromosomes do not • If no ori, must be incorporated into DNA via homologous recombination

  7. Homologous Recombination

  8. Horizontal Gene Transfer: DNA-Mediated Transformation • When bacteria take up naked DNA • What is naked DNA? • DNA free in the cell’s surrounding • Not contained in a cell or virus • How do you know it’s naked? • Add DNase=no transformation • Where does the DNA come from? • Other cells secrete it or when cells die they release it

  9. Can All Bacteria Take Up Naked DNA? • No, the cells must be competent • A physiological state that allows DNA uptake • What allows a cell to become competent? • Some cells are always naturally competent • Some cells sense their surroundings, respond by turning on genes necessary for competence

  10. T R A N S F O R M A T I O N

  11. Horizontal Gene Transfer: Transduction • Bacterial viruses aka bacteriophages/phage transfer bacterial genes from a donor to recipient

  12. First, Let’s Talk Phage • Phage is a virus that infects bacteria • Phage contains genetic material of DNA OR RNA (never both) • Genetic material is surrounded by a protein coat • Phage attaches to a cell and injects its genetic material

  13. Horizontal Gene Transfer: Transduction

  14. Horizontal Gene Transfer: Conjugation • Conjugation = “con”tact between donor and recipient cells • What is transferred? • Plasmids • Do they have ori? Yes • Most studied and understood: F plasmid (fertility) • Cell harboring the F plasmid: F+ • Cell without the F plasmid: F- • How the plasmid is transferred: F pilus (sex pilus)

  15. Horizontal Gene Transfer: Conjugation

  16. Activity (15 mins) • Your paper bag is a bacterium, we are Streptococcus pyogenes(strep throat) in a • Discs in your bag represent a plasmid • White: Plasmids without a gene for antibiotic resistance • Purple: Plasmids with a gene for penicillin resistance • Record here___________ the color of your discs • Go to another student and exchange a disk with another student’s bacterium: DO NOT LOOK IN BAG WHEN EXCHANGING • Repeat the exchange 4 additional times (for a total of 5) • No record the number and color of your discs here_________________________________

More Related