Long range-inverse PCR (LR-IPCR): extending the useful range of inverse PCR

The inverse PCR technique (IPCR) has proven to be very useful for the amplification of uncharacterized stretches of DNA upstream or downstream of regions that have already been cloned and sequenced. In practice, however, chromosome walking using standard IPCR is often a slow, repetitive process because only small DNA fragments are effectively amplified. The development of long and accurate PCR methodology has greatly expanded the range of DNA fragment sizes that is amenable to amplification by conventional PCR. We reasoned that combining long range PCR with IPCR would also extend the useful range of the IPCR technique. In this paper we demonstrate the utility of the hybrid, long range-inverse PCR (LR-IPCR) technique by generating clones containing long stretches of DNA flanking endogenous chicken proviral elements.