Long arm short arm of a gene/RF, not chromosome - (May/18/2007 )

I obviously know what long arms and short arms of chromosomes are. I am having trouble looking up what long and short arms of gene inserts or targeting vectors are refering to. Do they just refer to two different sized pieces of a gene if it is cut up... or a another piece of DNA is inserted into it, dividing it into two? That is my suspicion as I think I have seen it referring to a short piece and a long piece of a gene that is left over after a middle piece is cre-lox recombined out.

Thanks for clearing that up if you can, it's been bugging me and I can't find a good place that has an explanation.

Nevermind, solved my own problem. Check out this site if you need any help too: http://www1.wfubmc.edu/tgmcore/knockout/