This study describes a method for analyzing amplified DNA using immobilized sequence-specific oligonucleotide probes. The technique involves the polymerase chain reaction (PCR) to amplify DNA, followed by hybridization with labeled oligonucleotide probes immobilized on a nylon membrane. The probes are modified with long homopolymer tails to enhance their binding to the membrane, allowing the oligonucleotide probe to remain free for hybridization. The amplified DNA is then hybridized to the membrane under stringent conditions, and hybridization is detected nonradioactively using streptavidin-horseradish peroxidase conjugate and a colorimetric reaction. The method was applied to HLA-DQA genotyping and the detection of β-thalassemia mutations. For HLA-DQA genotyping, six major DNA types were analyzed, while for β-thalassemia, nine alleles were detected. The technique allows simultaneous screening of all known allelic variants at an amplified locus, significantly improving the efficiency of genetic analysis. The method uses biotinylated primers for PCR amplification, and the biotinylated DNA is detected by binding to streptavidin-horseradish peroxidase. The technique is nonradioactive, efficient, and suitable for high-throughput analysis. The study also discusses the use of terminal deoxyribonucleotidyltransferase to add homopolymer tails to oligonucleotides, which enhances their binding to the nylon membrane. The effectiveness of the method was demonstrated through experiments with various DNA samples, showing high hybridization efficiency and specificity. The method is applicable to a wide range of genetic analyses, including the detection of mutations in the β-globin gene and other genetic loci. The technique is robust, simple, and potentially automatable, making it suitable for forensic and clinical applications. The study highlights the advantages of this method, including its nonradioactive detection, high sensitivity, and ability to analyze multiple genetic loci simultaneously.This study describes a method for analyzing amplified DNA using immobilized sequence-specific oligonucleotide probes. The technique involves the polymerase chain reaction (PCR) to amplify DNA, followed by hybridization with labeled oligonucleotide probes immobilized on a nylon membrane. The probes are modified with long homopolymer tails to enhance their binding to the membrane, allowing the oligonucleotide probe to remain free for hybridization. The amplified DNA is then hybridized to the membrane under stringent conditions, and hybridization is detected nonradioactively using streptavidin-horseradish peroxidase conjugate and a colorimetric reaction. The method was applied to HLA-DQA genotyping and the detection of β-thalassemia mutations. For HLA-DQA genotyping, six major DNA types were analyzed, while for β-thalassemia, nine alleles were detected. The technique allows simultaneous screening of all known allelic variants at an amplified locus, significantly improving the efficiency of genetic analysis. The method uses biotinylated primers for PCR amplification, and the biotinylated DNA is detected by binding to streptavidin-horseradish peroxidase. The technique is nonradioactive, efficient, and suitable for high-throughput analysis. The study also discusses the use of terminal deoxyribonucleotidyltransferase to add homopolymer tails to oligonucleotides, which enhances their binding to the nylon membrane. The effectiveness of the method was demonstrated through experiments with various DNA samples, showing high hybridization efficiency and specificity. The method is applicable to a wide range of genetic analyses, including the detection of mutations in the β-globin gene and other genetic loci. The technique is robust, simple, and potentially automatable, making it suitable for forensic and clinical applications. The study highlights the advantages of this method, including its nonradioactive detection, high sensitivity, and ability to analyze multiple genetic loci simultaneously.