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This Week. Score Conjugation Plates, Start High Frequency of Recombination (HFR) experiment, Continue Nasonia experiment. H igh F requency of R ecombination (Hfr). ...bacteria exhibiting a high frequency of recombination ,
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This Week • Score Conjugation Plates, • Start High Frequency of Recombination (HFR) experiment, • Continue Nasonia experiment.
High Frequency of Recombination(Hfr) ...bacteria exhibiting a high frequency of recombination, • an alteration DNA sequence such that the genotype of subsequent individuals differs from the parent, …specifically, strains with a chromosome integrated F factor that is able to mobilize and transfer part of the chromosome to the F- cell.
...F factor integration site, ...host (bacteria chromosome) integration site. Hfr Cells F factor Bacterial Chromosome Inserted F plasmid
Double Crossover Recombination Requires Crossing over
F factor inserts in different regions of the bacterial chromosome, Also inserts in different orientations.
Origin of Replication Hfr Order of transfer strain H thr azi ton lac pur gal his gly thi 1 thr thi gly his gal pur lac ton azi 2 lac pur gal his gly thi thr azi ton 3 gal pur lac tonazi thr thi gly his
Indicates direction of transfer. A a A F factor A a Hfr F- Hfr DNA that is not incorporated in the F- strand, and DNA that has crossed out of the F- strand is digested.
A A Hfr F- F factor A transfers first. A A Hfr F- A transfers last. Leading Gene: the first gene transferred is determined empirically.
Hfr Order of transfer strain H thr azi ton lac pur gal his gly thi 1 thr thi gly his gal pur lac ton azi 2 lac pur gal his gly thi thr azi ton 3 gal pur lac tonazi thr thi gly his
E. coli Map • 0 minutes is at the threonine, • 100 minutes is required to transfer complete genome,