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

Area of Science:

• Forensic Science
• Genetics
• Molecular Biology

Background:

• Technological advancements from the Human Genome and International HapMap Projects have spurred interest in single nucleotide polymorphisms (SNPs) for forensic DNA typing.
• The forensic DNA typing community is evaluating SNPs as potential replacements for currently used short tandem repeat (STR) loci.

Purpose of the Study:

• To explore and compare the utility of SNP and STR markers for human identity testing.
• To assess the suitability of various SNP and STR loci and assays, including miniSTRs for degraded DNA.

Main Methods:

• Exploration of numerous SNP and STR loci and assays.
• Development of miniSTRs for degraded DNA samples.
• Evaluation based on power of discrimination, mixture component deciphering, and multiplex assay capabilities.

Main Results:

• STR loci demonstrate superior power of discrimination compared to SNPs for general human identity testing.
• STRs are more effective in deciphering mixture components and can be multiplexed to maximize information from limited biological material.
• SNPs show potential for specialized forensic applications.

Conclusions:

• Short tandem repeats (STRs) will likely continue to dominate human identity testing in the foreseeable future.
• Single nucleotide polymorphisms (SNPs) may find utility in specific forensic applications like mtDNA testing, Y-SNP lineage tracking, ancestry informative markers (AIMs), and phenotypic trait prediction.