Next-generation sequencing (NGS) and microarray technology both let researchers study genetics at a scale far beyond what single-gene methods like PCR can offer. They approach the problem differently, though, and understanding that difference matters when deciding which one fits a given genomics research study.
How Microarrays and NGS Work
A microarray is a chip covered with thousands of short DNA probes, each designed to bind a specific known sequence; fluorescence at each probe spot indicates how much of that sequence was present in the sample. NGS takes a different approach — it directly reads the sequence of DNA or RNA fragments, base by base, without needing to know in advance what you're looking for, making it possible to discover novel mutations, structural variants, or previously uncharacterized transcripts.
Why It Matters in Research
Massively Parallel, High Throughput
NGS can sequence entire genomes or thousands of targeted regions simultaneously, at a fraction of the time and cost of older methods.
Comprehensive Genomic Coverage
Whole genome, exome, and transcriptome sequencing provide a complete view of genetic and expression variation.
Detection of Rare Variants
Deep sequencing coverage allows detection of low-frequency mutations, critical for cancer genomics and rare disease research.
Scalability
NGS scales from small targeted gene panels to whole-genome sequencing, accommodating diverse research needs and budgets.
Enabling Novel Research Applications
NGS underlies emerging fields such as single-cell sequencing, epigenomics, and metagenomics.
Where Each Technology Is Typically Used
- Microarray — cost-effective, high-throughput screening of known gene expression changes or SNP genotyping across large sample sets
- Whole-genome/exome sequencing — discovering novel or rare mutations linked to disease, especially in cancer genomics
- RNA-Seq — unbiased transcriptome profiling, including discovery of novel transcripts and splice variants
- Metagenomic sequencing — characterizing entire microbial communities without needing to culture individual organisms
- Targeted/amplicon sequencing — deep, cost-efficient sequencing of a specific gene panel or region
NGS vs. Sanger Sequencing
| Feature | NGS | Sanger Sequencing |
|---|---|---|
| Throughput | Millions of reads in parallel | One sequence at a time |
| Cost per Base | Very low | High |
| Sensitivity to Rare Variants | High (deep coverage) | Limited |
| Common Use | Genome/exome/transcriptome sequencing | Targeted single-gene sequencing, validation |
Why the Distinction Matters
- Microarrays remain a fast, economical option when you already know which genes or variants you're interested in
- NGS costs more per sample but offers open-ended discovery power and single-base resolution
- NGS is the standard for novel variant discovery, cancer genomics, and comprehensive transcriptome studies
- Many labs use microarrays for initial large-scale screening and follow up positive hits with targeted NGS or qPCR for confirmation
Best Practices for NGS and Microarray Studies
- Ensure high-quality, sufficiently concentrated input nucleic acid
- Choose sequencing depth and coverage appropriate to the research question
- Use validated bioinformatics pipelines for alignment and variant calling
- Confirm key findings with an orthogonal method, such as Sanger sequencing or qPCR
Frequently Asked Questions
What is NGS used for?
NGS is used to sequence DNA or RNA at massive scale, supporting applications such as whole genome sequencing, gene expression profiling, cancer mutation detection, and microbiome analysis.
How is NGS different from Sanger sequencing?
NGS sequences millions of fragments in parallel at low cost per base, while Sanger sequencing sequences one fragment at a time with high per-base accuracy, better suited for targeted validation.
What are common NGS platforms?
Common platforms include Illumina (short-read sequencing-by-synthesis), Ion Torrent, and long-read technologies such as Oxford Nanopore and PacBio.
What is sequencing depth?
Sequencing depth refers to the average number of times a given nucleotide is read during sequencing; higher depth improves confidence in variant detection, especially for rare mutations.
Conclusion
Our sequencing and genomics services cover NGS, methylation analysis, and metagenomic sequencing workflows from sample prep through bioinformatics.