have amplified both the amount of data that can be generated from them as well as the power to extract information from the data. In the era of microsatellites, it was possible to establish that participants shared certain markers and segments of the genome not by chance but by descent. With the advent in the mid-2000s of genotyping chips, which could measure hundreds of thousands of single-letter variations (SNPs) across the genome, deCODE statisticians were able to accurately phase segments of the genome - to understand the parental source of segments - and then impute genotypes measured in some people across the entire population. This effectively multiplies the size and power of any study. When Illumina began selling machines that could economically sequence whole genomes, deCODE was able to directly sequence several thousand Icelanders and then impute whole genome sequence (WGS) data for virtually the entire population. This represents one of the largest single collections of WGS data in the world, and the first results of its analysis were published in 2015 in a special edition of Nature Genetics. The direct sequencing of tens of thousands of more people since then has enabled routine searches for ever rarer variants at an unprecedented scale. Discoveries and scientific contributions Genome research in general, and deCODE's global reputation as a discovery organization, took off with the arrival of SNP genotyping chips in the mid-2000s. These tools set off a worldwide boom in genome-wide association studies (GWAS), in which the entire genome is scanned to identify SNPs that those with a given disease tend to have one version of, while unaffected individuals tend to have another. In common diseases, as with many traits or phenotypes such as drug response, the difference is not one of causal certainty but of statistical odds representing increased or decreased risk versus the population average. The ability to conduct large studies and analyze the resulting data - from thousands of patients with a disease and many times more control subjects, ideally unaffected relatives - is therefore at a premium. deCODE's vast collection of DNA, medical and genealogical data that could be mined together - and enriched through repeated querying and imputation - was almost perfectly suited to this type of study. Since 2003, the company has discovered and published hundreds of variants linked to susceptibility to scores of diseases and conditions, including major ongoing contributions to understanding inherited risk