F’ and partial diploids
The F-factor in a Hfr chromosome can excise out to
become an autonomously replicating plasmid.
If a segment of the chromosome becomes part of the F-
plasmid during excision,the new element is called an F’-
plasmid.
This F’-plasmid can be conjugated to another bacterial
cell to form a partial diploid.
F-plasmid
F’-plasmid
chromosome
with deletion
Recombination
point
Hfr
chromosome
a
a a
Partial Diploids in bacteria are used in
complementation analysis
a
F’ plasmid
+ Bacterial cells = (by either conjugation
or transformation)
a
a
Partial diploid
for only one region
of the chromosome
The recipient bacterial
cells are recA- to prevent
recombination and re-integraton
of the plasmid into the host
chromosome.
Bacteriophage Genetics
Phage can take two different pathways
upon infection of a bacterial cell
,lytic or lysogenic
Generalized Transduction
introduction of genes from a
donor cell
occurs with phage which can
co-package DNA (rare event)
Packaged DNA is a random
fragment
Used to measure:
co-transduction frequencies
map distances
a-
b-
c-
a+
b+
c+
recipient donor
Phage lambda
Gene
knockout in
Bacteria