P1 vector?

[U6065606 at ucsvc.ucs.unimelb.edu.au]

I have heard that there is a plasmid -like vector able to carry
inserts of about 100kb.  It is apparently known as P1.  Can anybody
direct me to more information on this vector.

Thanks

Geoff McFadden
Plant Cell Biology Research Centre
School of Botany
University of Melbourne, Australia