SNP (Pronounced “snip”) Chips

What are they and why are they so important?

SNP stands for Single-Nucleotide Polymorphism

Polymorphism, the “P” in SNP, refers to locations within the DNA where the single nucleotide (the “SN” in SNP) varies from one individual to another. It is this variation of a single nucleotide that may signal the difference between disease-affected individuals and healthy individuals. Thus, identifying SNPs within the genome of individuals is critical in the hunt for DNA markers for genetic disease.

A DNA chip is a small piece of silicon glass to which a large number of synthetic single-stranded DNA oligonucleotides (“oligos”) have been chemically bonded. Oligos function as DNA probes: they “stick” (anneal) selectively only to those DNA molecules whose nucleotide sequences are exactly complementary. They can, therefore, be used to identify the presence of specific DNA sequences in a mixture of genes. In effect, oligos act like molecular “Velcro.” A computer “reads” the pattern of annealing and “reports” which alleles are present.

SNP chip technology is an extremely useful tool. It is used by researchers to locate DNA disease markers more quickly and thus makes many research projects more economically feasible. SNP chip technology will be vital to the BHF-supported search for a genetic marker for glaucoma in the Bouvier breed.