| Author | Message | ||
     Ernie Hamm (Unregistered Guest) Unregistered guest Posted From: ip72-219-233-252.dc.dc.cox.net |
The following was received by email on 19 June 2009, and posted by the webservant below: Articles addressing DNA and latent processing techniques have been published since 1989. However, the article that Mr. Clough may be making reference to could be: "Fingerprints and DNA: STR Typing of DNA Extracted from Adhesive Tape After Processing for Fingerprints", Ashira Zamir; Eliot Springer and Baruch Glattstein, Journal of Forensic Sciences, 45:3 (2000). There have been changes to the website due to corporate movements to the new identity (Forensics Sources), but you can still go to "www.redwop.com", find "Links of Interest" and then link to "Ernie Hamm's Reference Index". If you enter "DNA" in the search query, there will be a number of references on the subject, many relating to latent processing techniques. None which specifically address Wetwop, but some do address a similar suspension solution developing technique, SSP (Sticky Side Powder). Suspension solutions utilize material found in fingerprint powders, which have not been found harmful. Suspension solutions can use a detergent surfactant, but there is reference to studies on detergent substances cited in professional literature as not interfering with some types of subsequent DNA analysis. One such article (not found at the redwop.com source as it is in an updated list) is: "Obtaining Typable DNA from Bloodstains that Serologically Test Negative", Katie L. Coy, Kristen E. Lewis, Ashlee Fulmer, Amy Hudson and Tracey Dawson Cruz, Journal of Forensic Identification, 55:5 (2005). Good luck on your research. | ||
| Ernie Hamm (Unregistered Guest) Unregistered guest Posted From: adsl-154-212-213.jax.bellsouth.net |
Now, hopefully, for the 'rest of the story' on my attempted posting. For information on DNA and fingerprint techniques, you can visit http://www.redwop.com/reference_index.asp. At that site, enter DNA in the Reference Index block to display references to articles relating to DNA and the majority will deal with DNA and latent processing techniques. The article on detergent testing will not be displayed as it is at a later date from material presently included in the online references. I hope all this has been helpful to you, Rebecca. Posting edited by Webservant on 21 Apr 2008 to activate webpage links. Thanks for the valuable input and the wonderful reference resource, Ernie! | ||
| Ernie Hamm (Unregistered Guest) Unregistered guest Posted From: adsl-154-212-213.jax.bellsouth.net |
I should clarify Mr. Clough's post on Wetwop. I informed him that the main latent residue developing agent is a "form of carbon black" with "properties of black fingerprint powder" and also having "a surfactant (detergent) additive". I mention this because the contents of Wetwop are proprietary and I do not know the 'exact' properties. I did attempt a post on this subject, but it was rejected until review by the Webmaster because of external links. It is hoped that the post will accepted and subsequently posted, especially when the external link could also have been accessed through this site's home page. However, one part of the rejected post dealt with the detergent issue. Mr. Clough expressed caution, stating, "detergents had a high potential to remove DNA, until shown otherwise". My rejected post cited (among other information) the following article, "Obtaining Typable DNA from Bloodstains that Serologically Test Negative", Katie L. Coy, Kristen E. Lewis, Ashlee Fulmer, Amy Hudson and Tracey Dawson Cruz, Journal of Forensic Identification, 55:5 (2005). It seems that the research in Virginia even surprised the researchers when full DNA profile could be obtained from detergent/cleanser 'contaminated' stains. Now, evaluation of the WetWop solution is still necessary for a definitive conclusion for that specific process. Webservant note: Postings containing external links are automatically rejected by the software on this forum due to thousands of attempted postings for gaming web sites and other unsavory web links having nothing to do with friction ridges. When postings are rejected, the following window appears:  If you click on the back arrow in your web browser, you will not normally lose any of your posting and you can delete external links ...or you can modify the forbidden URL codes by removing "http:/" and changing "www.somewebsite.com" to www(dot)somewebsite.com. If the webservant notices such work-around (non-active) links to valid friction ridge-related websites, he will edit the link to make it active (sending him a note about the posting, to ed"at"onin.com, is also a good idea). One external link is too many. Rejected postings on this forum are not in limbo pending review... there is nothing waiting in a queue for webservant review. If you email the desired wording and external links to the Webservant via ed"at"onin.com, he will normally make the posting for you (probably not the same day... the webservant travels often and works many late hours). Your webservant regrets that this draconian restriction on external links is necessary, but it is required because there are otherwise not enough hours in the day to police external links to porn and gaming websites that are frequently added through automated programs targeting this and other similar forums. This is a non-profit website attempting to be an informative resource about friction ridge examination and identification. The webservant is granted permission to spend time maintaining these pages by his loving wife, but not unlimited time to do so. This all said, postings by Ernie Hamm, who was one of the webservant's early latent print examination instructors and who continues to teach him and other experts many things, are always welcome here for everyone's edification. | ||
| Gerald Clough (Unregistered Guest) Unregistered guest Posted From: dell-ics1.oag.state.tx.us |
Mr. Hamm, who provides a great deal of reference information on fingerprint technical matters, informs me that Wetwop is black powder and what is essentially detergent, basically a convenient version of "sticky-side" developer. He points out that black powder, as we know, has no effect on DNA viability, but that no specific testing is known on the wetting agent. However, I think we can look to DNA extraction processes for what may be essentially the equivalent of such testing. Surfacant detergents are, in fact, used to break fatty cell membranes to release DNA during one common method of DNA extraction. And skin secretions, that are largely both lipids and water soluble substances, are naturally attacked by surfacant detergents. So, I believe I would assume that sticky-side mixtures that contain detergents had a high potential to remove DNA, until shown otherwise, and I would carefully evaluate the best use of any tape evidence or perhaps see if I could reserve portions of the evidence for separate analysis. | ||
| Gerald Clough (Unregistered Guest) Unregistered guest Posted From: dell-ics1.oag.state.tx.us |
Someone asked this on another forum back in 2005 and got no answer. Because Wetwop is used on the adhesive side of tape, skin cells stuck to the adhesive would remain, and that is what is acted upon by Wetwop, the cells would remain as a potential source of DNA. We note that most other common latent development processes do not normally harm DNA recovery (see the Israeli study a fews years ago, to which I do not have a citation right at hand, but I believe it was in the IAI journal). It might be a good question for Lightening Powder, but I don't think there's anything very exotic in Wetwop. | ||
| Rebecca Glenn (Wylandfn) Member Username: Wylandfn Post Number: 1 Registered: 04-2008 |
Does anyone have any information regarding Wetwop having a destructive or harmful effect on DNA? I have searched for information regarding the subject with negative results. Any helpful information would be appreciated. Thank you. |
