Easy and Rapid Detection of Point Mutations in the Human beta-hemoglobin Gene with DNA-chips

Study was conducted on hemoglobinopathies the world`s most common class of single gene disorders. We selected four point mutations of the human beta-hemoglobin gene, giving rise to frequently occurring unstable beta-hemoglobin variants or beta-thalassemias. Our chip system is based on allele-specific oligonucleotide hybridization to detect single nucleotide polymorphisms (SNPs) and mutations. The probes attached to the chip surface consist of oligonucleotides containing the point mutations and the three corresponding control sequences. The labeled target cDNAs used for hybridization are derived from genomic or subcloned genomic DNA via asymmetric PCR, which is specially adapted for the synthesis of labeled single stranded target DNA. In addition to the useage of a chip reader, evaluation of the hybridized chip is adapted for using enhanced chemiluminescence. With this chip all four hemoglobin point mutations are easily detected and furthermore, homozygous alleles are distinguished from heterozygous alleles. Our SNP chip system is ready for rapid detection of all point mutations and SNPs occurring in the hemoglobin and other genes.