Transferred points stay exactly as they are in terms of UY and home resort.
The only piece that goes with yours is what UY the transfer will count for. For example, if you transfer in someone's 2011 points, that counts as your 2011 UY, even if you use those points prior to your own 2011 UY.
So, if you had a Sept UY and decided to get 2011 Feb UY points to use for a July 2011 trip, that would still count as your one and only 2011 UY transfer, even though you used those points during your 2010 UY.
That is why someone can get points from different UY's. The only thing that is of importance, IMO, is making sure you get points that will be valid for the time you want to use them.