What are the differences between microarray and next generation sequencing?

Basis of differentiation

Microarray

NGS

Definition

Microarray is a collection of microscopic DNA spots attached to a solid surface, which is used to measure the expression levels of large numbers of genes simultaneously 

NGS is a non-Sanger-based high throughput DNA sequencing technique which generates millions or billions of DNA strands to be sequenced in parallel 

Interactions with antigen

Micorarray is based on hybridization that is composed of a set of known targets

NGS is based on synthesis which uses DNA polymerase to integrate nucleotides and does not rely on information from previously known targets 

Applications 

Microarrays are primarily used for detecting chromosomal copy variants (deletions and duplications), and gene expression profiling   

NGS has a wider range of applications such as whole-genome sequencing, RNA sequencing, whole-exome sequencing 

Level of Resolution

Microarrays display moderate resolution, allowing the detection of large genomic alterations

NGS displays a much higher resolution, and is capable of detecting small-scale variations such as single-nucleotide variants and small insertions

Cost

Microarray technology is typically less expensive than NGS

NGS is more expensive due to the high cost of sequencing instruments and reagents