The oligonucleotide microarray, a high-throughput polymorphism detection technology, holds great promise for the characterization of complex genetic variance. To achieve greater sensitivity and specificity for it to be an effective platform technology we present results and discuss some of the factors influencing signal intensities and single-mismatch discrimination in array-based mutation/SNP detection. Probes with a series of concentrations were spotted onto the slide in order to find the optimal concentration with the identifiable satisfying signals and the stable ratios between matched and mismatched probes. It was found that under our experimental conditions, when the initial probe concentration is higher than the maximum immobilization capability of the slide (7.5 micrometer), the hybridization signal will be saturated and the ratio between matched and mismatched probes will be more stable than at a lower probe concentration. Considering the cost of probes and the systematic stability, a constant spotting concentration of 10 micrometer was selected. The stability of different types of mismatched oligo-DNA duplexes on the glass surface was also confirmed. The results show that the order of stability of mismatched oligo-DNA duplexes on a glass surface is in general agreement with previous reports conducted using liquid and polyacrylamide gel pads. This suggests that the influence of the mismatched base pair on the stability of the duplex in a solid hybridization system is similar to that in the solution hybridization environment.
Nucleic Acid Heteroduplexes/chemistry ; *Nucleic Acid Hybridization ; *Oligonucleotide Array Sequence Analysis ; Oligonucleotide Probes/chemistry ; *Polymorphism, Single Nucleotide ; Research Support, Non-U.S. Gov't

OBJECTIVETo confirm that PCR products with heterozygous mutations contain not only wide-type and mutant homoduplexes, but also two types of heteroduplexes.

METHODSAn insertion-deletion mutation in the exon 1 of KRT9 gene (497delAinsGGCT), which caused Chinese epidermolytic palmoplantar keratoderma (EPPK) was investigated by polymerase chain reaction (PCR), polyacrylamide gel electrophoresis (PAGE) and denaturing high-performance liquid chromatography(DHPLC).

RESULTSTwo heteroduplexes and two homoduplexes in the PCR product from the heterozygous mutation of the exon 1 of KRT9 (497delAinsGGCT) were detected.

CONCLUSIONPCR products from KRT9 gene with heterozygous mutations contain two types of heteroduplexes. It is without the need to perform heating and cooling PCR products obtained from heterozygous mutations in advance before the mutation screening steps such as denaturing gradient gel electrophoresis (DGGE), temperature gradient gel electrophoresis (TGGE), conformation-sensitive gel electrophoresis (CSGE), DHPLC and heteroduplex analysis (HA), etc.

Base Pair Mismatch ; Chromatography, High Pressure Liquid ; DNA Mutational Analysis ; Electrophoresis, Polyacrylamide Gel ; Heteroduplex Analysis ; Heterozygote ; Humans ; Keratin-9 ; Keratins ; genetics ; Mutation ; Nucleic Acid Heteroduplexes ; Polymerase Chain Reaction