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RNAi library clone error reporting/bacterial contamination

Julie Ahringer jaa at mole.bio.cam.ac.uk
Wed May 19 07:37:30 EST 2004

RNAi feeding library error reporting

In making the our RNAi feeding library, several quality control steps 
were carried out to reduce the risk of library clones with the 
incorrect insert. Despite these precautions, clone errors do occur at 
low frequency in the library (current estimate is 5%). Many of these 
appear to be very slow growing clones that were contaminated during 
amplification. After conducting RNAi screens with the feeding library, 
positive clones should be sequenced to verify the identity of the 

We are currently exploring the possibility of having all the RNAi 
clones in the library sequenced, as this would be beneficial to all 
library users. In the meantime, we have set up a facility to report and 
display clone errors 
(http://www.welc.cam.ac.uk/~ahringerlab/pages/rnai.html). Please submit 
any errors you find using this form. We will update the clone error 
display page to share this information anonymously and also re-sequence 
these clones to provide independent verification.

Bacterial contamination

It has been brought to our attention that the distributed chromosome V 
library plates (especially plates V-5 to V-8) are contaminated with 
non-E.coli bacteria. We have traced this to a low level contaminant in 
our master glycerol stocks that was amplified when copies were made for 
distribution. We are currently working hard to decontaminate chromosome 
V library plates and will forward MRC Geneservice clean stocks as soon 
as possible.  We apologize for any inconvenience caused.
Dr. Julie Ahringer
The Wellcome Trust/CR UK Gurdon Institute
University of Cambridge
Tennis Court Road
Cambridge CB2 1QR

phone  +44 01223 334142 (Office)
	         334144 (Lab)
fax    +44 01223 334089
jaa at mole.bio.cam.ac.uk

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