FUTURE DIRECTIONS AND NEW TECHNOLOGIES

• Jurisdiction: Australia

FUTURE DIRECTIONS AND NEW TECHNOLOGIES

Overview ....................................................................................................... [80.1200]

Massively parallel sequencing/next generation sequencing ........................ [80.1220]

Predictive DNA testing .................................................................................. [80.1240]

Rapid DNA/At Scene DNA Analysis ............................................................. [80.1260]

[80.1200] Overview

DNA can be transferred legitimately as a result of events unrelated to a crime. Furthermore, biological material containing DNA is readily transferable between individuals and objects (direct transfer), and can be further transferred by the intermediary to another person or object (secondary transfer). A number of peer-reviewed papers address this issue and provide a scientific framework in which assertions of these sorts can be assessed (eg, Goray, 2010; Goray, 2009).

Laboratories continue to look to improvements in the nuclear DNA process to be able to obtain results from degraded samples.

[80.1220] Massively parallel sequencing/next generation sequencing

In recent years, advances in technology have given rise to different and faster approaches to DNA sequencing. High throughput sequencing is referred to as Next Generation Sequencing (NGS) or Massively Parallel Sequencing (MPS). MPS technology allows the analysis of massive amounts of DNA, and its use is well entrenched in research. It is important to note that MPS represents a technology change to the current DNA analysis processes, in that the DNA currently analysed using methods and technology already described can also be analysed on an MPS platform.

There are two fundamental approaches to sequencing, one is to sequence the whole genetic code of an organism and the other is to target specific areas on the DNA. Forensic users are more likely to target areas of the DNA. The targeted areas can include the current set of (18) markers used for DNA profiling and databasing purposes, and/or an extended set of markers for profiling, and also other DNA tests used to determine female lineage (mitochondrial DNA) and the male line of inheritance (Y-chromosome). MPS can also incorporate newly developing systems for predictive DNA testing (such as those for hair and eye colour, and bio-geographic ancestry) using single nucleotide polymorphisms (SNPs) (see below). Most of these tests can be performed in a single analysis reaction using MPS, highlighting the potential advantages of MPS, that is, the ability to test for many hundreds of DNA markers simultaneously, thus increasing the information obtained from each sample.

Of the MPS methods currently available on the market, the two more forensically mature versions (front runners for forensic application) of this technology are from Illumina Inc, and Thermo Fisher Scientific™. The systems either read a fluorescence signal or detect a pH change when each nucleotide (A, C, G or T) is added in the sequencing reaction. These systems are beginning to be widely used in other testing environments such as clinical testing. MPS offers the potential for a significant improvement in DNA analysis; however, currently the methods are more expensive and take longer (up to 3-5 days) to develop a result than the current (capillary electrophoresis) methods (which take less than 1 day).

A significant issue that needs to be addressed is that MPS technology produces a large amount of data, which has to be stored, analysed and interpreted; significant data storage (terabytes) will be required. Secure cloud-based data storage and sharing provides one option and there are also efforts to...