Simplified construction and characterization of yeast artificial chromosome libraries

Three yeast artificial chromosome (YAC) libraries were constructed using two human cell lines and the pYAC-RC vector. The main differences from the previously described methods were: i) genomic DNA was digested in low melting point (LMP) agarose blocks with the rare cutting enzyme ClaI; ii) DNA was ligated in melted LMP agarose after agarase treatment; iii) spheroplast regeneration plating was done in calcium alginate thin layer. In addition, a panel of PCR primers was used to identify quickly the presence in the libraries of repetitive and single copy human DNA sequences.