GENETIC-ANALYSIS USING GENOMIC REPRESENTATIONS

Analysis of the genetic changes in human tumors is often problematical because of the presence of normal stroma and the limited availability of pure tumor DNA. However, large amounts of highly reproducible ''re presentations'' of tumor and normal genomes can be made by PCR from na nogram amounts of restriction endonuclease cleaved DNA that has been l igated to oligonucleotide adaptors. We show here that representations are useful for many types of genetic analyses, including measuring rel ative gene copy number, loss of heterozygosity, and comparative genomi c hybridization. Representations may be prepared even from sorted nucl ei from fixed and archived tumor biopsies.