Abstract
Background: Microelectronic DNA chip devices represent an emerging technology for genotyping. We developed methods for detection of single-nucleotide polymorphisms (SNPs) in clinically relevant genes.
Methods: Primer pairs, with one containing a 5′-biotin group, were used to PCR-amplify the region encompassing the SNP to be interrogated. After denaturation, the biotinylated strand was electronically targeted to discrete sites on streptavidin-coated gel pads surfaces by use of a Nanogen Molecular Workstation. Allele-specific dye-labeled oligonucleotide reporters were used for detection of wild-type and variant sequences. Methods were developed for SNPs in genes, including factor VII, β-globin, and the RET protooncogene. We genotyped 331 samples for five DNA variations in the factor VII gene, >600 samples from patients with β-thalassemia, and 15 samples for mutations within the RET protooncogene. All samples were previously typed by various methods, including DNA sequence analysis, allele-specific PCR, and/or restriction enzyme digestion of PCR products.
Results: Analysis of amplified DNA required 4–6 h. After mismatched DNA was removed, signal-to-noise ratios were >5. More than 940 samples were typed with the microelectronic array platform, and results were totally concordant with results obtained previously by other genotyping methods.
Conclusions: The described protocols detect SNPs of clinical interest with results comparable to those of other genotyping methods.
Allele-Specific X-Linked Gene Activity in Normal Human Cells Assayed by Expressed Single Nucleotide Polymorphisms (cSNPs)
