Mutations Part II
Bio119
I. Mutations by adding new DNA to the genome
A. DNA can be taken up by prokaryotes and incorporated into their
genomes
B. DNA that comes in either can replicate on its own, or is
recombined into the chromosome
1. To replicate on its own:
2. Otherwise, to persist it has to go into:
3. How this is done (Figure 15.6 and 15.7):
C. Getting DNA into cell by transformation:
1. Taking up plain old DNA
2. Natural Competence: story of Streptococcus pneumoniae
(Fig 15.14)
3. Artificially induced competence
D. Getting DNA into a cell by Conjugation
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Mutations Part II
Bio119
1. Transfer of genes from one prokaryote to another by a
mechanism involving cell-to-cell contact
2. What is transferred?
3. How conjugation works (Figure 15.9):
4. How scientists figured out cell-to-cell contact was required
for conjugation. (Box 15.1 U tube experiment)
E. Getting DNA by Transduction:
F. Using bacterial mutagenesis
1. Common type: gene replacement in bacteria (Fig. 15.11 and
15.12)
a) Method for adding or deleting a gene
b) Why do this?
G. Random transposon mutagenesis (Fig. 15.17 and 15.18)
1. What is a transposon?
a) An genetic element that moves from one site into
another
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Mutations Part II
Bio119
b) The Tn is has two inverted repeats
c) Usually has some antibiotic resistance marker in
between IR
d)
e) The Tn is also engineered without the transposase so
that it won’t transpose again.
f)
2. Screen for mutants (takes longer to do)
3. Selection for mutants (harder to do with for Tn mutagenesis)
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