Year of Award


Document Type


Degree Type

Doctor of Philosophy (PhD)

Degree Name


Department or School/College

Department of Anthropology

Committee Chair

Meradeth Snow

Commitee Members

Randall Skelton, Kelly Dixon, David Xing, Joseph Pasternak


Contamination, DNA, Storage


University of Montana


Studies have been conducted on DNA cross-contamination throughout the criminal investigation process in order to evaluation the possibility that DNA from one sample could potentially influence the outcome of another. However, no published studies have examined the potential for contamination during the storage of genetic evidence after samples have been taken from crime scenes or suspects. This study is a continuation of a preliminary project, which examined storage drying time in relation to cross-contamination. The current study tested temperature and humidity for the potential of cross-contamination during storage prior to extraction. Prior to storage, 50 μl of male saliva was aliquoted to buccal swabs and then dried for 20 minutes in a Dry-Fast swab dryer. Each variable tested consisted of five buccal swabs that were introduced to DNA and five swabs that remained unopened, in order to see if the male DNA could then be detected on the unopened swabs. Cross-contamination was not detected below 8 °C or 35% relative humidity. Any DNA that was detected was unable to produce a STR profile either as result of nonspecific amplification or extremely low levels of DNA, suggesting that if it did move, it was not enough DNA to alter results. However, further research is needed to determine if higher levels of humidity impact the movement of DNA.



© Copyright 2022 Samantha Leigh Allison Ramey