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Investigation of Strategies for Improving STR Typing of Degraded and Low Copy DNA from Human Skeletal Remains and Bloodstains

Forensic STR analysis is limited by the quality and quantity of DNA. Significant damage or alteration to the molecular structure of DNA by depurination, crosslinking, base modification, and strand breakage can impact typing success. Two methods that could potentially improve STR typing of challenged samples were explored: an in vitro DNA repair assay (PreCR™ Repair Mix) and whole genome amplification. Results with the repair assay showed trends of improved performance of STR profiling of bleach-damaged DNA. However, the repair assay did not improve DNA profiles from environmentally-damaged bloodstains or bone, and in some cases resulted in lower RFU values for STR alleles. The extensive spectrum of DNA damage and myriad combinations of lesions that can be present in forensic samples appears to pose a challenge for the in vitro PreCR™ assay. The data suggest that the use of PreCR™ in casework should be considered with caution due to the assay’s varied results. As an alternative to repair, whole genome amplification (WGA) was pursued. The DOP-PCR method was selected for WGA because of initial primer design and greater efficacy for amplifying degraded samples. Several modifications of the original DOP-PCR primer were evaluated. These modifications allowed for an overall more robust amplification of damaged DNA from both contemporary and historical skeletal remains compared with that obtained by standard DNA typing and a previously described DOP-PCR method. These new DOP-PCR primers show promise for WGA of degraded DNA.

Identiferoai:union.ndltd.org:unt.edu/info:ark/67531/metadc799472
Date08 1900
CreatorsAmbers, Angie D.
ContributorsBenjamin, Robert C., Budowle, Bruce, 1953-, Gill-King, Harrell, Turnbough, Meredith A., McIntire, Sarah
PublisherUniversity of North Texas
Source SetsUniversity of North Texas
LanguageEnglish
Detected LanguageEnglish
TypeThesis or Dissertation
Formatxiii, 112 pages : illustrations (some color), Text
RightsPublic, Ambers, Angie D., Copyright, Copyright is held by the author, unless otherwise noted. All rights reserved.

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