Genotypningsarraysystem

A genotyping array system is a high-throughput platform used to determine the genetic variants present in individuals at many genomic loci simultaneously. It primarily focuses on single-nucleotide polymorphisms (SNPs) but can also assay other known variants, such as small insertions and deletions, depending on the array design.

How it works: DNA is extracted from samples and prepared for analysis. Labeled DNA fragments are hybridized to a microarray containing probes that correspond to specific variant alleles. Assay chemistries produce allele-specific signals, which are detected by a scanner. Software then calls the genotype for each SNP across the samples, often after quality control steps and, when needed, statistical imputation to infer untyped variants using reference panels.

System components typically include the microarray itself with its probe set, reagents for hybridization and washing, an automated or semi-automated processing workflow, a scanner or reader for signal detection, and analysis software for genotype calling, QC, and downstream data handling. Imputation is commonly used to augment directly typed data by inferring additional variants from a reference dataset.

Platforms and formats: commercial systems such as Illumina’s Infinium and Thermo Fisher’s Axiom are widely used. These systems differ in probe chemistry and assay design but share the objective of generating dense genotype data across large numbers of samples.

Applications: genotyping arrays support genome-wide association studies, pharmacogenomics, population genetics, ancestry inference, and clinical testing for known disease-associated variants. They enable large-scale studies at relatively low cost per data point but are limited to predefined variants and may exhibit ascertainment bias. They are complemented by sequencing approaches when discovery of novel variants is required.