Microarray (Gene Chip / SNP Chip)
Definition
A solid-phase hybridisation platform carrying thousands to millions of oligonucleotide probes at spatially registered positions. Hybridisation of a labelled target simultaneously queries all probe positions; the spatial map converts signal positions to sequence identity. Used for genome-wide SNP genotyping, HLA typing, and forensic phenotyping model development.
- Platform type
- Solid-phase hybridisation array
- Probe density
- Thousands to millions of positions
- Readout
- Spatial signal map converted to sequence identity
- Forensic uses
- SNP genotyping, HLA typing, phenotyping models
Common questions
How does a microarray differ from DNA sequencing?+
A microarray only reports whether a labelled target hybridises to a predetermined set of known probe sequences, so it can genotype variants it was designed to detect but cannot discover a novel or unexpected sequence the way sequencing can.
Why use microarrays for forensic phenotyping research?+
Genome-wide SNP microarrays let researchers test hundreds of thousands of markers against traits like eye or hair colour in one experiment, which is how the SNP panels behind externally visible characteristic prediction tools were originally developed and validated.
Related terms
- Minisatellite (VNTR)
- A hypervariable genomic locus characterised by tandem repeats of a 10-60 bp core sequence, with the number of repeat units varying between...
- Molecular Hybridisation
- The formation of a double-stranded nucleic acid molecule from two complementary single strands, driven by hydrogen-bond formation between base pairs (A-T, G-C...
- mRNA Body-Fluid Profiling
- The RT-PCR-based descendant of Northern blotting: tissue-specific messenger RNA transcripts are reverse-transcribed and amplified from crime-scene stains to identify body fluid of...
- Southern Blot
- A technique (E.M. Southern, 1975) in which restriction-digested DNA fragments are separated by gel electrophoresis, transferred to a membrane, and hybridised with...
- Stringency
- The extent to which hybridisation conditions favour only perfectly complementary probe-target pairs over partially mismatched ones. High stringency (elevated temperature and/or low...
- Western Blot (Protein Immunoblot)
- SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of proteins followed by electrotransfer to a PVDF or nitrocellulose membrane, then antibody-based detection of a specific protein...