Over the last ten years, the field of human genomics has made unbelievable progress in identifying genetic variants that influence disease susceptibility and other traits (see, e.g. this review). The technological advance that drove this progress was the development of genotyping microarrays: a technology for the measurement of hundreds of thousands to millions of genetic variants in a single person.
The benefits and limitations of genetic studies using this technology (often confusingly called genome-wide association studies [1]) have been debated since before anyone even tried one (see examples from 2000, 2008, and 2017). But it’s generally believed that, if one accepts the basic goals and assumptions of a genome-wide association study, the most cost-effective and powerful technology to use is a genotyping array.