Prokaryotic Genetics and Gene Expression

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Prokaryotic Genetics and Gene Expression

• Prokaryotic Genetics

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Prokaryotic Genetics Tools Bacterial Conjugation

• Bacteria , in general, reproduce asexually, but
  in order to increase diversity and share the gene
  pool, they transfer a set of genes which are
  called F for fertility (page 341)
• These genes can exist on a small, circular piece
  of DNA that replicates independently from the
  bacterial chromosome, or they can be integrated
  into the chromosome.

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Prokaryotic Genetics Tools Bacterial Conjugation

• The bacterium containing this F gene (called the
  "male" bacterium) shoots out a pilus out to sieze
  a neighbouring bacterium (page 341) .
• The two cells then are drawn together, and the
  grappling hook forms a channel through which DNA
  is transferred. This process is called bacterial
  conjugation.

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Bacterial Conjugation - manifestations of the
fertility factor

• Hfr - The F element has become integrated into
  the genome and when conjugation occurs, the F
  genes start travelling across the pilus, dragging
  the rest of the genome behind it.
• Eventually, the pilus breaks so most often the
  entire genome is not transferred. (but lots of
  extra genes go through Page 341)

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Bacterial Conjugation - manifestations of the
fertility factor

• F - Also called the F episome. This is a small
  circular piece of DNA that contains the fertility
  genes and a few other genes.
• These other genes are transferred very
  efficiently from one bacterium to the next
  because the length of the transferred DNA is
  short enough that it can move across the breach
  before the pilus breaks.
• F - This is a small circular piece of DNA
  carrying only the fertility genes.