genotiping

Genotiping, also written as genotyping, is the process of determining the genetic constitution of an individual or a sample at specific loci or across the genome. It identifies which genetic variants are present at predefined positions in the DNA, distinguishing different genotypes or haplotypes.

Common approaches include PCR-based assays (such as allele-specific PCR and real-time qPCR), SNP genotyping arrays that assay thousands to millions of single-nucleotide polymorphisms, and sequencing-based methods like targeted Sanger sequencing or high-throughput next-generation sequencing, which can provide broad genotype information. Microsatellite typing and haplotype analysis are also used in certain contexts. The choice of method depends on the research or diagnostic question, required resolution, and cost.

Genotyping has wide applications in medicine, such as carrier screening, pharmacogenomics to predict drug response, and tumor genotyping to identify driver mutations. In agriculture and breeding, genotyping informs selection for traits like yield, disease resistance, or quality. In research, genotyping underpins genome-wide association studies, population genetics, forensic analysis, and lineage tracing. Data are typically reported as alleles at predefined loci or as comprehensive variant profiles from sequencing.

Interpretation and limitations: genotype data are compared to reference genomes or databases, and accuracy depends on marker density, sample quality, and laboratory rigor. Validation with controls and appropriate statistical analysis is important. Ethical and privacy considerations arise because genetic information can reveal hereditary traits and risks about individuals and their relatives, requiring informed consent and careful data governance. The field has advanced rapidly with the rise of high-throughput sequencing, expanding both scope and scale of genotyping.