[bionet.molbio.methds-reagnts] Strange Phenomenon

mkw6d@krebs.acc.Virginia.EDU (Martyn K. White) (05/09/91)

We have been trying to isolate a chicken cDNA from a lambdaGT10
library using a rat cDNA homologue as a probe. A positive plaque 
was picked, the phage grown up, the lambda DNA isolated, the 3kb
EcoRI insert fragment isolated and subcloned into pBS.  Sequencing
reactions from a miniprep were run from both ends and when run
against genbank, it proved to be 99.7% homologous to E.coli RNA 
polymerase B!!?!

Has anyone else experienced pulling out an E.coli gene like this?
What might cause this?

Our current hypothesis is that this is a subcloning artefact
caused by contaminating E.coli genomic DNA in our lambda DNA prep
and we are doing Southern blots with our rat probe and
are screening more minipreps of the pBS ligation transformants
to see what is going on.

Comments welcome,
		thanks

		Martyn




	Martyn K. White, Box 441, U.Va, Cville VA 22908
	     		(804) 924 8710	
                 mkw6d@krebs.acc.Virginia.EDU
		      mkw6d@Virginia.EDU