GenomeWalker Kits provide a simple, PCR-based gene discovery tool for finding novel and unknown sequences adjacent to known sequences [e.g., expressed sequence tag (EST)] by walking upstream or downstream in the genomic DNA of the known sequence. GenomeWalker allows for individual steps of up to 6 kb in genomic DNA using long-distance PCR. Walks can be extended simply by taking multiple steps or using new primers based on the sequences obtained in previous steps.