The use of massively parallel sequencing in Forensic DNA typing - what will the future hold?

The current standard methodology in forensic DNA typing relies on amplification of short tandem repeat (STR) markers by the polymerase chain reaction (PCR) and allele sizes (i.e., length-based) determined for each locus using capillary electrophoresis (CE). Massively parallel sequencing (MPS), also known as next generation sequencing (NGS), allows high throughput sequencing of STR amplicons, which can identify nominal length-based (LB) genetic variation but equally as well inter-allelic sequence (sequence-based; SB) variation. The increased effective number of alleles per marker for some STR loci improves discrimination power, which may be invaluable in some cases of kinship analysis and for mixture de- convolution. Furthermore, allelic variation captured using MPS may be useful towards understanding of STR mutations and their rates and may contribute to evolutionary studies using STR markers. One issue with current massively parallel sequencing (MPS) is the need to capture flanking region sequence variation to exploit the full power of forensically relevant STR loci. The application of such data will increase our knowledge and understanding of each locus, gain additional genetic information about population specific genetic parameters, increase the power of discrimination of a locus, and potentially aid in mixture de-convolution efforts. The underlying genetic variation needs to be described through studies on various population groups.

Learning Objectives:

1. Understand the advances in sequence-based technologies in Forensic DNA typing

2. Understand the major commonalities and differences between current and futuristic DNA typing methods

3. Acknowledge the complexities of the human genome for forensic human identity applications