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Previous studies on DNA damage and repair have involved in vitro laboratory procedures that induce a single type of lesion in naked templates. Although repair of singular, sequestered types of DNA damage has shown some success, forensic and ancient specimens likely contain a number of different types of lesions. This study sought to (1) develop protocols to damage DNA in its native state, (2) generate a pool of candidate samples for repair that more likely emulate authentic forensic samples, and (3) assess the ability of the PreCR Repair Mix to repair the resultant lesions. Complexed, native DNA is more difficult to damage than naked DNA. Modified procedures included the use of higher concentrations and longer exposure times. Three types of samples, those that demonstrated damage based on short tandem repeat (STR) profile signals, were selected for repair experiments: environmentally damaged bloodstains, bleach-damaged whole blood, and human skeletal remains. Results 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. [ABSTRACT FROM AUTHOR]

In 1995, the historical shipwreck of La Belle was discovered off the coast of Texas. One partial human skeleton was recovered from alongside cargo in the rear portion of the ship; a second (complete) skeleton was found atop coiled anchor rope in the bow. In late 2015, comprehensive forensic genetic testing began on multiple samplings from each set of remains. For the partial skeleton recovered from the ship's rear cargo area, results were obtained for 26/27 Y-STRs using traditional CE; with MPS technology, results were obtained for 18/24 Y-STRs, 56/56 ancestry-informative SNPs (aiSNPs), 22/22 phenotype-informative SNPs (piSNPs), 22/27 autosomal STRs, 4/7 X-STRs, and 94/94 identity-informative SNPs (iiSNPs). For the complete skeleton of the second individual, results were obtained for 7/17 Y-STRs using traditional CE; with MPS technology, results were obtained for 5/24 Y-STRs, 49/56 aiSNPs, 18/22 piSNPs, 15/27 autosomal STRs, 1/7 X-STRs, and 66/94 iiSNPs. Biogeographic ancestry for each set of skeletal remains was predicted using the ancestry feature and metapopulation tool of the Y-STR Haplotype Reference Database (YHRD), Haplogroup Predictor, and the Forensic Research/Reference on Genetics knowledge base (FROG-kb). Phenotype prediction was performed using piSNP data and the HIrisplex eye color and hair color DNA phenotyping webtool. mtDNA whole genome sequencing also was performed successfully. This study highlights the sensitivity of current forensic laboratory methods in recovering DNA from historical and archaeological human remains. Using advanced sequencing technology provided by MiSeq™ FGx (Verogen) and Ion S5™ (Thermo Fisher Scientific) instrumentation, degraded skeletal remains can be characterized using a panel of diverse and highly informative markers, producing data which can be useful in both forensic and genealogical investigations. [ABSTRACT FROM AUTHOR]