woman in white dress shirt standing near table

DNA Genotyping and Sequencing. A technician at the Cancer Genomics Research Laboratory, part of the National Cancer Institute's Division of Cancer Epidemiology and Genetics (DCEG), washes arrays used in genome-wide association studies (GWAS). These studies search the genome for small variations, called single nucleotide polymorphisms or SNPs, that occur more frequently in people with a particular disease than in people without the disease.