This study modified the degenerate oligonucleotide primed-polymerase chain reaction (DOP-PCR)-based whole genome amplification method for improvement of downstream genome-wide analysis of low copy number DNA samples ( 0.50 intralocus heterozygote peak ratios were observed for most DNA input quantities examined. These results show that modifications of the traditional DOP-PCR reaction (dcDOP-PCR) to include the use of a more degenerate primer (10 N), 12 nonspecific cycles, and a proofreading enzyme allows for a more complete, balanced chromosome amplification from limited and/or compromised clinical and biological samples.

This study investigated whether a difference exists in the ability to obtain quality mitochondrial DNA (mtDNA) sequence data from hair shafts due to specific melanin content differences. Eumelanin, the pigment in darker hairs, protects nuclear DNA in the skin by absorbing and scattering UV radiation. In contrast, sensitized pheomelanin, the predominate melanin in red hairs and some blond hairs, is unable to prevent DNA damage in skin upon exposure to UV radiation. It has been reported in the literature that darker hairs (predominate eumelanin content) have a higher mtDNA sequencing success rate than lighter colored hairs. However, others have reported to the contrary when different methodologies are used. In this study, 2-cm hair fragments were cut from dark brown, red, and gray white hairs and typed using standard casework mtDNA sequence analysis methods. All 30 hair fragments produced quality mtDNA sequence data on first attempt from the second half of hypervariable region 1. These results are likely due to the apparent shielding of mtDNA by the hard protein of the hair shaft fiber from radiation-induced damage, regardless of melanin type, after 10-months minimal solar exposure. Nonetheless, this study may serve as a guide for future quantitative studies that investigate hair mtDNA photodamage in circumstances of increased solar, chemical, environmental, or mechanical damage.

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