The analysis of mitochondrial DNA (mtDNA) sequence from human hair was proven to be a valuable complement to traditional microscopy comparisons of hair in forensic cases when DNA typing was not possible. Unfamiliar at times to a forensic DNA scientist, were the subjects of hair microscopy and hair embryogenesis. The continuous growth and replacement of human hairs involved cellular transformation and regeneration events. Analysis of mtDNA sequence data potentially involves complex questions of interpretation. The objective of this review was to bring hair microscopists and forensic DNA scientists closer together. To better help forensic scientists associate mtDNA sequence heteroplasmy data with physical characteristics of a hair, macroscopic and microscopic hair specimen classifications were provided. These classifications were seen as possibly being useful when evaluating the relative success in sequencing different types and/or forms of human hairs. In summation, as forensic scientists produce greater amounts of mtDNA sequence data, they can start to try and answer many questions about the relationship of hair histogenesis and mtDNA analysis. References