Collecting DNA from fingerprints

[bficken]

Hello Everyone,

We are revamping our procedures regarding the collection of touch DNA. How many people out there are collecting swabs for possible DNA from fingerprints?

Those that are NOT doing it - what is your reasoning?

Those that ARE doing it - what is your reasoning and at what stage do you collect the swabs? Many of the chemicals we use to develop fingerprints can destroy DNA. So, do you only use the non-destructive chemicals and then have to justify why you limited the fingerprint development? Do you swab only a small portion of the print as to not hinder the comparison, but then you can use destructive chemicals after the swabs?

I'm just wondering what most people outside our lab are thinking these days.

Thanks!

[timbo]

I'm a little confused by your statement of 'many chemicals we use can destroy DNA'.

Unless there are other studies I'm unaware of, the chemicals that can inhibit/destroy DNA are magnetic powder; and then anything with a water wash (DNA dissolves into water), such as Ardrox and physical developer. Additionally, short wave UV is also destructive on the imaging side of things (ie. RUVIS). That's it!
But in all cases here, except for perhaps physical developer, a perfectly suitable alternative is readily available - eg. Rhodamine 6G instead of Ardrox. My (and anecdotally many other peoples') experience with PD is a very small number of usable real casework fingerprint results - so losing PD from a sequence would not be losing a whole lot of potential for obtaining fingerprints. I must admit, I'm not sure if a study has been performed on whether Oil Red O is destructive for DNA or not, but that could then provide an alternative to PD if it is non-destructive.

Are you aware of other chemicals that can destroy DNA, and if those claims are backed up by studies?

Fingerprints only provide between 1.1 to 75ng of DNA (from a paper by van Oorschot & Jones), so I would think that only swabbing a small portion of the print is dangerous in that you are limiting your potential for DNA retrieval from an already limited starting point (compared to blood/semen/etc.). Contact DNA already has smaller success percentages, why reduce that success percentage?

[NRivera]

A quick search of published articles in the JFI might address some of your questions:

The Effects of Ninhydrin Processing on Common a-Amylase Tests

Author(s): Bitner, S.; Clark, J.; Priestley, M.; Ziencik, B.
Type: Technical Note
Published: 2013, Volume 63, Issue 5, Pages 503-513

Evaluation of the Impact of Different Visualization Techniques on DNA in Fingerprints

Author(s): Norlin, S.; Nilsson, M.; Heden, P.; Allen, M.
Type: Article
Published: 2013, Volume 63, Issue 2, Pages 189-204

Assessment of the Possibility of DNA Accumulation and Transfer in a Superglue Chamber

Author(s): Gibb, C.; Gutowski, S.; van Oorschot, R.
Type: Technical Note
Published: 2012, Volume 62, Issue 5, Pages 409-424

DNA versus Fingerprints

Author(s): Ferraro, J.
Type: Commentary
Published: 2012, Volume 62, Issue 5, Pages 405-408


I hope that helps!