This image is excerpted from a U.S. GAO report: www.gao.gov/products/GAO-15-80 ANTHRAX: Agency Approaches to Validation and Statistical Analyses Could Be Improved Note: SNPs and INDELs (insertions or deletions) are small differences between genomes. A duplication is a kind of insertion where a specific sequence of the deoxyribonucleic acid (DNA) has been repeated. These changes in genetic sequence are an important part of evolution.