Classical view of bacteria genome
Sponsored Links
This presentation is the property of its rightful owner.
1 / 29

“Classical” view of bacteria genome PowerPoint PPT Presentation

  • Uploaded on
  • Presentation posted in: General

“Classical” view of bacteria genome. Single chromosome May have plasmids and phage Simple gene structure Genes have recognisable phenotype. Vibrio y Bacteriodes. Bacterial genomes come in different conformations. Circular chromosomes the traditional view: E . coli Linear chromosomes

Download Presentation

“Classical” view of bacteria genome

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.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript

“Classical” view of bacteria genome

  • Single chromosome

  • May have plasmids and phage

  • Simple gene structure

  • Genes have recognisable phenotype

Vibrio y Bacteriodes

Bacterial genomes come in different conformations

  • Circular chromosomes

    • the traditional view: E. coli

  • Linear chromosomes

    • Borrelia

  • Plasmids

    • circular and linear forms

Bacterial genomes can have several chromosomes

  • “Chromosomes must harbour some essential genes”

    • ribosomal RNA (rrn)

  • “Plasmids should not be required for viability”

    • only encode supplementary functions

    • can be very large (1-2 Mb)

Bacterial genomes

  • Most species have one chromosome

    • eg E. coli

      • 1x circular chromosome with rrn, housekeeping genes

  • Some species have 2 chromosomes (a few 3)

    • eg Agrobacterium tumefaciens

      • 2x chromosomes each with rrn and housekeeping genes

        • 1x circular 3Mb

        • 1x linear 2Mb

      • 2x plasmids, circular 200kb, 450kb

Bacterial genomes come in many different sizes

  • Range 0.6Mb – 9Mb

  • Bigger genomes encode more genes

  • < 2Mb specialist species

    • restricted ecological niche (Mycoplasma)

    • fastidious growth (Haemophilus influenzae)

    • obligate intracellular parasites (Chlamidia)

  • 3 – 5Mbgeneralist species

    • broad metabolic potential, few organic growth requirements (E. coli)

  • > 5Mbspecies with developmental cycles

    • (Streptomyces: mycelial growth, spores, complex bioactive compounds)

Burkholderiaxenovorans LB400 (>20 PCBs) (recuèrada de suelo contaminado en Nueva York)

General genome


E. coli genome

  • Packed coding genes. Sequencing has identified 4390 protein coding genes in E. coli K-12 genome (4,6 Mb)

Organization of bacterialgenomes: coding genes

Organization of bacterialgenomes: non-coding genes

Organization of bacterialgenomes: repeatsequences



Organization of bacterialgenomes

“Perhaps one of the most important lessons has been that genetic diversity, at the

level of large-scale variation amongst even genomes of the same species, is far greater

than was thought. The classical textbook view of evolution relying on the relatively

Slow accumulation of mutational events at the level of individual bases scattered

throughout the genome has changed.

Thisdiversityisgeneratedby a variety of mechanisms, including mobile genetic

elementsand bacteriophages.”

Ten years of bacterial genome sequencing: comparative-genomics-baseddiscoveries

Binnewies et al. (2006) FunctIntegrGenomics (2006) 6: 165–185

Organization of bacterialgenomes: mobileelements

Profagos integrados en los genomas de distintas cepas de

Salmonella Typhi

Genomicislands (pathogenicityislands)

Organization of bacterial

genomes: mobileelements

(RNA intermediate)

Type II Introns


DGRs: Diversity-generating


Coros et al. (2009) Mol Cell, 34: 250-6

  • Login