We have designed a YAC circularization vector, pCIRC3, allowing enrich
ment of the YAC DNA by exonuclease digestion of the linear yeast chrom
osomes. Due to the presence of P1 replicon sequences in this vector, t
he circular YACs would replicate as PACs in Escherischia coli. (C) 199
7 Elsevier Science B.V.