Mixture Analysis Master for Android

Updated: 09.02.2012

Forensic DNA interpretation going portable

Not currently active because of other projects...

Mixture Analysis Master is a 'proof of concept' demo application to aid forensic DNA mixture interpretation. Based on the principles described by Peter Gill et al. [1] two-person DNA mixtures can be interpreted using peak height data and simulation of residuals conditioned on genotype combinations.

The statistical software R [2] is well suited for development of new models through its flexibility and power. However, R has a steep learning curve and it can be time consuming to create user-friendly interfaces. My vision is to implement published and unpublished models developed in various projects in a user-friendly software. Efforts will be made to improve some of the models. The aim is to release the software as open source in the future.

The application, written for Android devices, demonstrate several key concepts:

• Data transfer using QR codes
• Portability
• User-friendliness

Mixture Analysis Master can be downloaded from Android Market here.

More information about the author can be found here.

Data transfer using QR codes

Sharing data files manually involve some pitfalls, especially sharing between systems with different language and region settings. Common problems are usually caused by decimal, delimiter, or white space characters. By sharing data optically by QR codes, these problems are avoided. Since QR codes can store approximately 1.800 characters [3] a complete DNA profile, including allele names and peak heights as well as sample name and marker names, can be encoded as a single QR symbol. Free web site services or a small program could be used to encode previously exported text files from e.g. GeneMapper® ID-X into QR codes that can be read by this software.

Portability

Android powered devices comes in all shapes and sizes, from minimal smartphones to powerful tablets [4]. Forensic DNA evidence can conveniently be explored or presented outside the office, without access to a desktop PC.

User-friendliness

Taking advantage of mobile devices touch capabilities it is possible to load a batch of samples and explore the genotype combinations for each marker using nothing more than the tip of your finger. By scanning the QR codes containing the DNA profiles you don't even have to do a manual export/import. It is fast and easy to share DNA profile examples used for education. Students will be able to download their own interpretation software directly to their own mobile smartphone or tablet and start using it instantly. No need to learn complicated commands or unfamiliar user interfaces.

Screenshot showing residual simulation of locus D3S1358 for Sample05. All possible genotype combinations are shown in the legend. The profiles average mixture proportion (Mx) is calculated and marked in the plot (optional). An arbitrary residual threshold can be set and shown in the plot to indicate if genotype combinations are likely or not (optional).

Version History

Version 0.1 - Altenberg: First release. Demo application.

Version 0.2 - Altenberg: Bug corrections.

Version 0.3 - Altenberg: Bug corrections. Swipe problem fixed.

Please report any bugs, including hardware used to me.

References

[1] P Gill, R Sparkes, R Pinchin, T Clayton, J Whitaker, J. Buckleton, Interpreting simple STR mixtures using allele peak areas, Forensic Science International, Volume 91, Issue 1, 9 January 1998, Pages 41-53, ISSN 0379-0738, 10.1016/S0379-0738(97)00174-6. (http://www.sciencedirect.com/science/article/pii/S0379073897001746)

[2] http://www.r-project.org/

[3] http://en.wikipedia.org/wiki/QR_code

[4] http://en.wikipedia.org/wiki/Comparison_of_Android_devices