help!!!

[D2011]

can anyone please help me to unterstand this:

if you want to carry out the p element mediated ends out targeting, you should in one step determine the location of the inserted p element by crossing them to balancer strain.
But why should the p element not be inserted into the same chromosome where also the target gene is located?

i can not understand this

[Fredrik]

My answer would be, that by using a insertion on another chromosome than you want to target you will then screen for a movement, meaning that it have moved to the
chromosome you wanna target, thereby you can probably discard many candidates that for example not have excised properly. Using a insertion on the same chromosome will not do so. The faster you can eliminate false candidates down to a low number the better.