Horizontal Gene Transfer Reading Notes Flashcards
Why is horizontal gene transfer important?
to acquire genes that may be important for specific environment;may be retained if gives competitive edge
what bacteria species no competent?
e coli
what can do to make competent
cacl2 (alter mem to allow import foregin DNA) or electroporation (shoot DNA in)
What is distinct about transformation?
cell do not choose what DNA is imported and what genes to keep.
what can use foreign DNA for?
- repair genome if similar
- as food
- evolution to survive diff env
What process of transformation in gram positive bac?
Create a transformasome which includes protein to
- capture
- create pore
how is DNA brought into the pore?
nuclease degrades one strand and pulls the other through the pore ; once inside, the strand can be incorporated via recombination
What is growth phase dependent competence?
secretion of CF ; more bacteria = more CF = stim transformasome formation aka quorum sensing
why quorum sensing
bc if dilute waste energy bc unlikely encounter DNA but more = higher chance cousins die and you take their DNA
What makes gram negative species diff in transformation?
- must overcome outer membrane and
- typically natural transformers are always competent or competent when starved
- specificity of transformation
how many origins of replication does F factor have
two; oriV (for regular replication and division) and oriT for transfer
What is the last portion transferred in recipient?
OriT
what does relaxase hold onto ?
5â end
What happens when F plasmid integrate into host chromo?
it becomes Hfr and basically the entire chromosome becomes a F factor.
What is the last to be inserted into recipient in hfr?
f factor; rare for receipient become hfr cell or F+ when conjugate with an Hfr
