Three brands of processed human hair extensions were evaluated microscopically and genetically for their probative value in forensic casework. Microscopic analysis of hair morphology determined that the internal and surface characteristics of the human hair extensions were consistent with human head hair and failed to identify any distinguishing features (pitting, striations, indentations, internal variations) that differentiated the extensions from natural human hair. Chemical analysis identified carbon, oxygen, sulfur, aluminum, and calcium as the main elemental components of the extensions which is consistent with human hair. There were no elements detected that were unique to the processed human hair extensions. mtDNA extracted from the hair extensions was sequenced and compared to the revised Cambridge sequence (rCRS) to identify single nucleotide polymorphisms (SNPs). SNPs were used to assign haplotypes and distinguish regional affiliations associated with the extensions in an attempt to establish the ethnicity of the hair donor’s maternal lineage. Hair extensions were associated with multiple geographic regions. Sequencing also identified hairs from multiple donors in each package.
Caitlin Porterfield – 2014