Direct selection of DNA sequences conserved between species

Abstract

An essential requirement in the analysis of genomes is the identification of functionally important sequence elements, which are often evolutionarily conserved. We describe here the development of a novel procedure for the selective isolation of conserved sequences which is based on hybridization of PCR-amplifiable DNA fragments from the whole genome of one species to biotinylated DNA from a genomic region of another species. The interspecies DNA hybrids are immobilized and the PCR-amplifiable DNA fragments are eluted, amplified and after further hybridization-amplification rounds cloned. This method was used for the generation of sublibraries of conserved sequences from mouse and pig DNA from regions corresponding to cosmids from the human Xq28 region. Mouse and pig homologs of sequences containing exons of known human genes, as well as exons from novel genes have been identified.