Variations of scalp, pubic and axillary hair

Abstract

Hair examinations and comparisons conducted by forensic scientists often provide investigative and associative information. Apart from its length and its natural color, hair displays a morphologic diversity both macroscopically and microscopically. Pseudogenization of <phihHaA type I hair keratin gene inactivation highlights dramatic differences and is thought to be one of the strongest reasons for localization of hair in human. Therefore, humans have several different types of hair that can be classified depending on their body position and form. Size, angle of penetrance through the skin, embryological time of first appearance, and structural variations in the hair follicles are all taken into account when classifying hair types. However, the classification of differential types of hair quantitative traits in human is yet to be undertaken. An attempt has been made in the present study to understand the variation by using the histomorphological and quantitative variables of 540 hair strands (180 each scalp, axillary and pubic hair) of 18 adult Bengalee Hindu caste females. Apart from variation in histomorphological variables, quantitative variables regarding shaft and medulla diameter demonstrated variation in terms of being significantly higher (p < 0.05) in pubic hair compared to that of axillary and scalp hair. Therefore, the present study envisaged that variability in histomorphological and quantitative traits in different areas of human could be one of the important criteria for personal identification in forensic research.

Age, Health and Attractiveness Perception of Virtual (Rendered) Human Hair

“…Hair diameter changes across the lifespan and varies between-individuals (Messenger, 2011; Mistry et al, 2012; Robbins, 2012). However, the evidence for a direct relationship of age and hair fiber diameter is mixed with regard to the type and direction of the relationship.…”

Clinical and anthropological perspectives on chemical relaxing of afro‐textured hair

“…Hrdy opined that hair form was determined by multiple genes, and that tightly curly hair form had evolved convergently in African and Melanesian populations because of similar environmental pressures, but did not speculate on the possible functional significance of hair form. Since Hrdy's research, comparative studies of hair form have focused on forensic applications, not on phylogeny and function. The latter questions are being approached slowly, as variant genes associated with distinct hair phenotypes are identified.…”

Keratins of the human occipital hair medulla: androgenic regulation ofin vitrohair keratin K37 expression

“…In this study, we examined the keratin expression in medullated human scalp hairs. We used Asian occipital hair which, besides being androgen‐insensitive, is more frequently medullated than in other ethnicities . We found that the medulla of occipital and sexual hairs exhibited essentially identical keratin patterns.…”

“…Unlike most mammals, in man only androgen‐dependent sexual hairs, i.e. beard, pubic and axillary hairs, are regularly medullated, while the frequency of medullation in scalp hairs varies among individuals and ethnicities . Recently, we reported that out of the 54 human keratins, 12 epithelial keratins [comprising members of the outer and inner root sheath (ORS, IRS), the companion layer (cl), and the almost ubiquitously expressed keratin K80, as well as 12 hair cortex keratins] are present in the medulla of beard hairs .…”

“…beard, pubic and axillary hairs, are regularly medullated, while the frequency of medullation in scalp hairs varies among individuals and ethnicities. 1,2 Recently, we reported that out of the 54 human keratins, 12 epithelial keratins [comprising members of the outer and inner root sheath (ORS, IRS), the companion layer (cl), and the almost ubiquitously expressed keratin K80, 3 as well as 12 hair cortex keratins] are present in the medulla of beard hairs. 4 Remarkably, the keratin composition of individual medulla cells is extremely variable with both epithelial and hair keratins behaving in a highly promiscuous manner with regard to heterodimer and intermediate filament (IF) formation as well as keratin chain interactions in IF bundles.…”