Degeneration of Nuclei and Mitochondria in Human Hairs

Abstract

It is generally accepted that nuclei degrade in developing hair shafts but the point at which such occurs has not been investigated. The fate of mitochondria in the keratinizing hair shaft has been less clear. This study uses transmission electron microscopy to investigate when nuclei and mitochondria are no longer visible in the developing hair shaft. Serial sections were obtained from anagen head hairs absent follicles in order to determine the sequence of degradation of nuclei and mitochondria in the hair shaft by starting at the root bulb and proceeding toward the hair tip. It was demonstrated that nuclei and mitochondria become invisible in the keratinizing hair shaft at about the same time. This was found to occur fairly early in the process at the level of the hair shaft where the hair cuticle becomes permanent.

A Simple Method to Extract DNA from Hair Shafts Using Enzymatic Laundry Powder

“…It might be caused by the keratinisation process for its cytolysis[24]–[26]. If the template was cracked, an amplification failure would occur as we described.…”

The Post-Apoptotic Fate of RNAs Identified Through High-Throughput Sequencing of Human Hair

“…In humans, hair does not contain viable cells [11] and undergoes 1–2 months of maturation prior to its emergence from the scalp, compared to 1 week in mice [29]. While human hair may be a better model to study post-terminal differentiation hair, studies of human hair versus mouse hair posed unique challenges.…”

“…Skin-specific endonucleases such as DNase1L2 target genomic DNA during cornification [3], [9], and in the absence of DNase1L2 , nuclear DNA persists in the hair and causes hair fragility [10]. The external hair is defined as the hair shaft and consists largely of the proteinaceous remnants of three cell types [11]. The three hair shaft cell types, the outer cuticle, cortex and central medulla, originate from a self-renewing progenitor population called the matrix [12].…”

Exploring the mitochondrial DNA variability of the Amazonian Yanomami

“…As a result, the extraction and typing of nuclear DNA from hair shafts that have been severed from their roots has often been unsuccessful (Graffy and Foran, 2005;Guan et al, 2013;Nozawa et al, 1999). This means that an analysis of mtDNA from hair shafts is feasible (Kurihara, 2013;Linch, 2009;Linch et al, 2001;Wilson et al, 1994). This means that an analysis of mtDNA from hair shafts is feasible (Kurihara, 2013;Linch, 2009;Linch et al, 2001;Wilson et al, 1994).…”