genotypningsarray

Genotypningsarray, commonly referred to as a genotyping array or SNP array, is a high-throughput platform used to determine genetic variation at predefined loci across the genome. It enables simultaneous interrogation of hundreds of thousands to millions of single nucleotide polymorphisms (SNPs) and other variants, depending on the design.

The array comprises a solid surface (often glass) with DNA probes fixed at defined coordinates. Genomic DNA from a sample is labeled and hybridized to the probes. After washing, the signal is measured by a scanner, and algorithms assign genotypes by clustering fluorescence intensities for each SNP.

Arrays can be genome-wide, providing dense SNP coverage, or targeted panels that focus on specific regions or functionalities. Probes may include SNPs, copy number variants, and other markers. Content can be produced commercially or customized for a study.

Common applications include genome-wide association studies (GWAS) to identify disease-associated variants, pharmacogenomics to predict drug response, population genetics, and ancestry inference. Imputation uses reference panels to infer untyped variants, increasing effective coverage.

Limitations include dependence on predefined variants, reduced ability to detect rare or novel changes, and ascertainment bias toward populations represented in the probe set. Sensitivity to DNA quality and array design, and cost considerations relative to sequencing, can also influence results.

In recent years, sequencing-based approaches such as whole-genome sequencing and genotyping-by-sequencing offer broader discovery, while genotyping arrays remain cost-efficient for large cohorts and well-characterized populations.

Ethical considerations include informed consent, privacy, and data sharing, particularly for identifiable genetic information.