NCJ Number
197320
Journal
Journal of Forensic Sciences Volume: 47 Issue: 5 Dated: September 2002 Pages: 964-967
Date Published
September 2002
Length
4 pages
Annotation
This paper reports on a study that demonstrated the utility of microscopic hair examinations and the strength of combining microscopic analysis with mtDNA sequencing.
Abstract
The microscopic comparison of morphological characteristics of human hairs has been accepted both scientifically and legally for decades. The advent of mitochondrial DNA (mtDNA) sequencing provides an additional test in the repertoire for assessing source association between a questioned hair and an individual. Neither the microscopic nor molecular analysis alone, or together, achieves absolute positive identification; however, these methods together can provide complementary examinations. Mitochondrial DNA typing, for example, can often distinguish between hairs from different sources although they have similar morphological characteristics. In contrast, hair morphology comparisons can often distinguish between samples from different individuals who are maternally related when mtDNA analysis is uninformative. The current study examined human hairs submitted to the FBI Laboratory for analysis between 1996 and 2000. Of the 170 hair examinations, there were 80 microscopic associations; of these, only 9 were excluded by mtDNA. Sixty-six hairs that were considered either unsuitable for microscopic examinations or yielded inconclusive microscopic associations provided mtDNA results. Only six hairs did not provide sufficient mtDNA, and only three yielded inconclusive results. Consistency was obtained in exculpatory results with the two procedures. The study concluded that both the microscopic and molecular analysis of hairs is useful in forensic investigations, because each relies on independent types of information. The mtDNA sequences provide information about the genotype of microscopic examination assesses physical characteristics of an individual's hair in his/her environment (phenotype). 4 tables and 17 references