Gold nanoparticle-assisted primer walking for closing the human chromosomal gap

The finished sequence of the human genome still contains 260 euchromatic gaps. All the PCR-based genome walking techniques used to close gaps have common limitations, such as low efficiency and low specificity. We herein describe a strategy to solve this problem by employing gold nanoparticles (AuNPs) to improve the efficiency in primer walking amplification. We used this strategy to close a gap in human chromosome 5 containing a DNA stretch composed of the 12SAT repeat. The obtained gap sequence is highly conserved among several mammalian genomes. The demonstrated AuNP-assisted primer walking strategy is capable of effectively improving the specificity of PCR amplification and enriching the yield of target DNA fragments; it offers a new avenue for closing gaps left by current sequencing methods.