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Proteomic Analysis of Hair Shafts From Monozygotic Twins: Expression Profiles and Genetically Variant Peptides.

NCJ Number
252459
Date Published
Unknown
Annotation
This study tested and validated recent proteomic approaches for extracting quantitative transcriptional and genetic information from hair samples of monozygotic twin pairs, which would be predicted to partition away from unrelated individuals if the datasets contain identifying information.
Abstract
The forensic association of hair shaft evidence with individuals is currently assessed by comparing mitochondrial DNA haplotypes of reference and casework samples, primarily for exclusionary purposes. In the current study, protein expression profiles and polymorphic, genetically variant hair peptides were generated from 10 pairs of monozygotic twins. Profiling using the protein tryptic digests revealed that samples from identical twins had typically an order of magnitude fewer protein expression differences than unrelated individuals. The data did not indicate that the degree of difference within twin pairs increased with age. In parallel, data from the digests were used to detect genetically variant peptides that result from common nonsynonymous single nucleotide polymorphisms in genes expressed in the hair follicle. Compilation of the variants permitted sorting of the samples by hierarchical clustering, permitting accurate matching of twin pairs. The results demonstrate that genetic differences are detectable by proteomic methods and provide a framework for developing quantitative statistical estimates of personal identification that increase the value of hair shaft evidence. (publisher abstract modified)
Date Created: January 28, 2021