A question about homologous recombination

[Mega]

What came to my mind some days ago:


The plasmid pVIB contains all the sequences for bioluminescence from Vibrio fischeri. What if you put the plasmid into Vibrio Fischeri?

Is there a chance that it is inserted into the chromosome (say attached to LuxA), and can other sequences get lost because of the substitution (e.g. LuxR; regulation, decreasing light output)?

[Anselm Levskaya]

> Is there a chance that it is inserted into the chromosome (say attached to
> LuxA), and can other sequences get lost because of the substitution (e.g.
> LuxR; regulation, decreasing light output)?

Plasmid - chromosome recombination is certainly a possibility in large
homologous stretches. However, in gram-negative bacteria it isn't all
that efficient. It happens very rarely.

When people do "recombineering" in e.coli they do so by first
expressing three lambda phage recombination genes and then introducing
the thing-to-swap-in as a -linearized- version of the DNA. Linear DNA
swaps in much more efficiently.

Yeast, on the other hand, swaps exogenous DNA into its chromosome with
surprising efficiency, which is why yeast genetics is the most
advanced among any organism - it just works.

-a

[shreyans chordia]

This is a double edged sword for yeast genetics as the insert is also unstable and faces the chance of disintegrating from the chromosome after few generations of growing the yeast.
(Thats the reason why they use BAC clones rather than YAC ones for sequencing.)