Vector-Alu PCR: a rapid step in mapping cosmids and YACs.

Economical procedures for mapping large numbers of cosmids and YACs, using panels of somatic cell hybrids are of practical importance in genome mapping. We developed a method based on direct PCR of individual cosmid colonies with primers complementary to the cosmid vector and 2 primers complementary to the extreme 5 prime and 3 prime parts of the Alu consensus sequence (1). We also applied this method on samples of YAC DNA, either liquid or in agarose blocks. The cosmid vector is p2CpG, a derivative of pCpG and pKNUNl (2, Dauwerse, unpublished), its primers: ML and RL. The YAC vector is YAC4, its primers: YL5 and YL3. The primers for the ALU repeat ALU5 and ALU3. The primers PDJ33 and PDJ34 suggested by Dr P. de Jong (personal communication) are also used for YACs. The sequences of the primers are depicted in Table 1. The method was used to map the human