SNaPshot Multiplex System for SNP Genotyping

What is SNaPshot® SNP Genotyping?

SNaPshot® SNP Genotyping is a highly accurate, primer extension-based method developed by Applied Biosystems (ABI) for detecting single nucleotide polymorphisms (SNPs). Also known as single-base extension (SBE) or mini-sequencing, this technology enables the simultaneous analysis of multiple SNPs within a single reaction, making it an efficient solution for targeted genotyping studies.

The technique begins with PCR amplification of the DNA region containing the SNP of interest. A specially designed extension primer is then hybridized immediately adjacent to the target SNP site. During the extension reaction, a single fluorescently labeled dideoxynucleotide (ddNTP) is incorporated into the primer, corresponding to the nucleotide present at the polymorphic position. Because ddNTPs lack a 3′ hydroxyl group, primer extension terminates after the addition of a single base.

The fluorescently labeled extension products are subsequently separated by capillary electrophoresis and detected based on their fluorescent signals. The emitted fluorescence identifies the incorporated nucleotide, allowing accurate determination of the SNP genotype. Owing to its high specificity, multiplexing capability, and reproducibility, SNaPshot® Genotyping is widely used for SNP validation, mutation analysis, population genetics, molecular breeding, forensic studies, and biomedical research.

How Does a SNaPshot® Assay Work?

The SNaPshot® assay is a primer extension-based genotyping method that enables accurate identification of single nucleotide polymorphisms (SNPs). The workflow consists of several optimized steps to ensure precise and reliable SNP detection.

1. Primer Design

Target-specific extension primers are designed to bind immediately adjacent to each SNP site. Primers are carefully optimized and may vary in length, allowing multiple SNPs to be distinguished simultaneously during capillary electrophoresis.

2. Multiplex PCR Amplification

The genomic regions containing the target SNPs are amplified using multiplex PCR. This approach enables several SNP loci to be amplified within a single reaction, improving efficiency and reducing processing time.

3. Single-Base Extension

Following PCR, a single-base extension reaction is performed using fluorescently labeled dideoxynucleotides (ddNTPs). Each ddNTP carries a unique fluorescent dye representing one of the four DNA bases (A, T, C, or G). The extension primer incorporates only one nucleotide complementary to the SNP position before extension terminates.

4. Capillary Electrophoresis

The fluorescent extension products are separated by capillary electrophoresis. Each fragment is identified according to its size and fluorescent signal, producing an electropherogram in which peak position and color correspond to the specific SNP and nucleotide.

5. Data Analysis

Specialized software automatically interprets the electropherogram to determine SNP genotypes. This analysis provides highly accurate and reproducible results while supporting multiplex detection of multiple SNPs in a single assay.

SNaPshot® technology typically enables simultaneous analysis of up to 16 SNPs in one reaction, making it an excellent choice for medium-throughput SNP genotyping projects.

SNaPshot® Genotyping Services

N2Jenomics Lab Pvt. Ltd. offers comprehensive SNaPshot® SNP Genotyping services for targeted genetic analysis across a wide range of research applications. Using advanced single-base extension technology and optimized laboratory workflows, we deliver high-quality, reproducible, and cost-effective SNP genotyping results for projects ranging from hundreds to thousands of samples.

Our services include:

• Custom Primer Design – Optimized extension primers developed specifically for your target SNPs.
• Multiplex PCR & Single-Base Extension – Carefully optimized assays to ensure high accuracy and reproducibility.
• High-Resolution Capillary Electrophoresis – Precise detection of fluorescent extension products for reliable genotype identification.
• Comprehensive Data Analysis – Automated genotype calling and expert review using advanced analysis software.

Our workflow is ideal for studies involving 8–16 SNPs across medium- to large-scale sample cohorts and can be customized to meet the specific requirements of your research.

Advantages of SNaPshot® Genotyping

• High Genotyping Accuracy

SNaPshot® technology delivers highly accurate SNP identification with excellent reproducibility, making it a trusted method for targeted genotyping and variant validation.

• Multiplex Analysis

Multiple SNPs can be analyzed simultaneously in a single reaction, increasing throughput while reducing reagent consumption, processing time, and overall project cost.

• Flexible Project Scale

The platform accommodates studies ranging from a few hundred to several thousand samples, providing flexibility for projects of varying sizes.

• Broad Compatibility

SNaPshot® assays are suitable for a wide variety of SNP targets and perform reliably across different species and research applications.

• Cost-Effective Solution

Compared with sequencing-based approaches, SNaPshot® offers an economical alternative for targeted SNP validation while maintaining high analytical performance.

• Rapid Turnaround

Optimized laboratory workflows and automated data analysis enable efficient processing and timely delivery of high-quality genotyping results.

Applications of SNaPshot® Genotyping

SNaPshot® technology supports numerous genomic research applications, including:

• Genetic association and candidate gene studies
• SNP validation following GWAS or sequencing projects
• Population genetics and evolutionary biology
• Pharmacogenomics and precision medicine research
• Plant and animal breeding programs
• Molecular marker validation
• Mutation screening and targeted variant analysis
• Agricultural and biomedical genomics

Its combination of accuracy, flexibility, and multiplex capability makes SNaPshot® an effective solution for targeted genetic studies across both academic and industrial research.

SNaPshot® Genotyping Workflow

The SNaPshot® workflow consists of a series of optimized laboratory steps designed to ensure accurate SNP detection:

• Genomic DNA extraction and quality assessment

• Multiplex PCR amplification of target genomic regions containing the SNPs of interest

• PCR product purification using enzymatic treatment to remove residual primers and unincorporated nucleotides

• Single-base extension reaction using allele-specific extension primers and fluorescently labeled ddNTPs

• Capillary electrophoresis to separate extension products according to fragment size

• Automated fluorescence detection and generation of electropherograms

• Genotype calling and comprehensive data analysis using specialized software

Each SNP genotype is determined by the position of the extension product and the fluorescent color of the incorporated nucleotide. This robust workflow provides accurate, reproducible, and scalable SNP genotyping and is commonly used for targeted analysis of approximately 3–30 SNP loci within a single project.

Service Specifications

Analysis Pipeline

Deliverables

• Raw data files (.fsa)
• Electropherogram files (.pdf)
• Primer sequences used in amplification and reaction systems
• Genotyping results (.excel)

1. Can the SNaPshot® assay detect sample contamination?

Yes. SNaPshot® genotyping can help identify potential DNA contamination by examining the fluorescence peak patterns generated during capillary electrophoresis. The presence of unexpected or imbalanced peak ratios may indicate mixed DNA samples or external contamination. Although SNaPshot® is not specifically designed as a contamination detection assay, these quality control indicators can assist in evaluating sample integrity and data reliability.

2. Can SNaPshot® detect previously unknown genetic variants?

SNaPshot® is primarily designed to genotype known SNPs with predefined target sites. However, if the DNA sequence surrounding a suspected variant is known, the assay can be developed to determine the nucleotide present at that specific position. It is not intended as a genome-wide variant discovery tool but is highly effective for validating and characterizing targeted polymorphisms.

3. Is SNaPshot® suitable for whole-genome SNP analysis?

No. SNaPshot® is a targeted SNP genotyping technology developed for analyzing selected genetic variants with high accuracy. It is ideal for validating candidate SNPs, mutation screening, and multiplex genotyping of a defined set of markers. For comprehensive genome-wide SNP discovery or large-scale variant profiling, technologies such as SNP microarrays and Next-Generation Sequencing (NGS) are generally more appropriate due to their much broader genomic coverage and higher throughput.

4. How many SNPs can be analyzed in a single SNaPshot® assay?

Depending on assay design and optimization, SNaPshot® technology can simultaneously analyze multiple SNPs in a single reaction, typically supporting up to 16 SNPs in standard multiplex assays. This multiplex capability improves efficiency, reduces reagent consumption, and lowers the overall cost of targeted genotyping projects.

5. What types of research commonly use SNaPshot® SNP Genotyping?

SNaPshot® is widely used in a variety of genetic research applications, including:

• Candidate SNP validation
• Genetic association studies
• Population and evolutionary genetics
• Plant and animal breeding
• Pharmacogenomics research
• Mutation confirmation
• Molecular marker analysis
• Biomarker validation

Its combination of high accuracy, multiplex capability, and cost-effectiveness makes it an excellent choice for targeted SNP analysis across numerous research fields.