Genomic libraries and the development of species-specific probes

Abstract

Abstract The development of standard methods for reliable cloning and propagation of DNA fragments of various sizes has transformed our understanding of gene structure and regulation. The ability to generate representative libraries of sequences comprehensively covering the genome regardless of size, complex ity, or type of organism has enabled population geneticists to undertake fine resolution analysis of sequence variation. The purpose of this chapter is to describe general protocols for the construction and screening of genomic libraries and for the development of species-specific probes. Although the construction of libraries was traditionally regarded as technically demanding, modern high-quality enzymes, commercially prepared packaging extracts, competent cells, and complete cloning kits have made genomic cloning universally accessible. A high quality representative library of clones avail able for rapid re-screening whenever new sequences suitable for population analysis are described is ample reward for the time and effort invested in the initial library construction.