BRL RNA ladder hybridizes to my probe

[Lana C Stallard]

I wonder if anyone has had this happen? I am using Gibco BRL RNA weight 
standards (made from phage lambda DNA spliced to an RNA transcript). I get 
significant hybridization with a mouse DNA probe (a cDNA probe of 
angiotensin converting enzyme) to the ladder when i transfer the ladder 
onto a Northern blot. Why would there be so much sequence similarity between lambda and a mouse gene? or could my probe still contain some sequences of the vector it was produces in (Bluescript 
plasmid) which is similar to the phage DNA? My boss is convinced i have a 
very non-specific probe but i think there must be a reason. 
	Thanks for any comments or ideas you may have. 
	Lana Stallard