Minimum homology bases needed for homologous recombination - (Nov/21/2013 )

Hi there,

May i know what is the minimum homology bases needed for a homologous recombination in pseudomonas? Due to some difficulty, i only 155bp for upstream region while for my downstream i have around 600bp. can homologous recombination happen? in my lab, the rule of thumb used was, 300bp-1000bp. I need all the experts' help! please help me

The 300-1000 bp rule is pretty well accepted, but this (as I understand it) is mostly to ensure that the recombination event is likely to take place in a region where it won't affect the bit you are trying to change.  The shorter the flanking arms are, the higher the chance that the recombination event will take place near an end, and potentially change the bit you are looking at.

I think 150 bp should be ok, but you will need to confirm that there haven't been any other changes in the surrounding regions as a result of the recombination.