Representational difference analysis using minute quantities of DNA.

Representational difference analysis (RDA) is a differential hybridization method which can effectively isolate unique DNA sequences from complex and highly related genomes or cDNA libraries. A major drawback of the RDA analysis is the requirement for pure driver and relatively pure tester samples, ruling out the analysis of whole tissue biopsies. To circumvent this problem, we have modified the technique for the analysis of very small quantities of DNA so that pure cell populations isolated by micromanipulation from tissue sections can be analyzed. Using this modified technique, as few as 50 diploid cells ( approximately 500 pg of DNA) can be analyzed.