STRs vs. SNPs: thoughts on the future of forensic DNA testing

Abstract

Largely due to technological progress coming from the Human Genome and International HapMap Projects, the issue has been raised in recent years within the forensic DNA typing community of the potential for single nucleotide polymorphism (SNP) markers as possible replacements of the currently used short tandem repeat (STR) loci. Our human identity testing project team at the U.S. National Institute of Standards and Technology (NIST) has explored numerous SNP and STR loci and assays as well as developing miniSTRs for degraded DNA samples. Based on their power of discrimination, use in deciphering mixture components, and ability to be combined in multiplex assays in order to recover information from low amounts of biological material, we believe that STRs rather than SNPs will fulfill the dominant role in human identity testing for the foreseeable future. However, SNPs may play a useful role in specialized applications such as mitochondrial DNA (mtDNA) testing, Y-SNPs as lineage markers, ancestry informative markers (AIMs), the prediction of phenotypic traits, and other potential niche forensic casework applications.