High-throughput phenotyping methods for quantifying hair fiber morphology

Lasisi, Tina; Zaidi, Arslan; Webster, Timothy H.; Stephens, Nicholas B.; Routch, Kendall; Jablonski, Nina G.; Shriver, Mark D.

doi:10.1101/2020.11.24.392191

Cited by 2 publications

(3 citation statements)

References 30 publications

(47 reference statements)

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“…A recent study of hair originating from people from mixed European and African origin ( n = 140) suggested that there was no causal effect between hair curl and ellipticity once the effect of hair origin was removed [19] thus, for the time being, geometric fibre characteristics should only be viewed as independent.…”

Section: Methodsmentioning

confidence: 99%

How different is human hair? A critical appraisal of the reported differences in global hair fibre characteristics and properties towards defining a more relevant framework for hair type classification

Daniels¹,

Fraser²,

Westgate³

2022

Intern J of Cosmetic Sci

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This review critically appraises the reported differences in human hair fibre within three related domains of research: hair classification approaches, fibre characteristics and properties. The most common hair classification approach is based on geo-racial origin, defining three main groups: African, Asian and Caucasian hair. This classification does not account sufficiently for the worldwide hair diversity and intergroups variability in curl, shape, size and colour. A global classification into eight curl types has been proposed but may be too complex for reproducibility. Beyond that, hair cross-sectional shape and area have been found to have an inverse relation to curl: straighter fibres are circular with larger cross-sectional area, whilst the curlier fibres are elliptical with smaller cross-sectional area. These geometrical differences have been associated with bilateral vs homogenous distribution of cortical cell in curly vs straight hair respectively. However, there is no sufficient data demonstrating significant differences in hair amino composition, but proteomic studies are reporting associations of some proteins with curly hair. Eumelanin's relative abundance has been reported in all hair colours except for red hair which has a high pheomelanin content. Higher tensile and fatigue strength of straight hair are reported, however, curly hair fragility is attributed to knotting, and crack and flow formations rather than the structural variations.African hair has been found to have the highest level of lipids, whilst the water sorption of Caucasian hair is the highest, and that of Asian hair the lowest. Not all comparative studies clearly report their hair sampling approaches. Therefore, to strengthen the robustness of comparative studies and to facilitate cross-study data comparisons, it is recommended that the following hair defining characteristics are reported in studies: hair cross sectional diameter/area, curl type, hair assembly colour, as well as where possible donor data (age/gender) and sample pooling approach. AbstraitCette revue évalue de façon critique les différences rapportées sur les fibres capillaires humaines dans trois domaines de recherche connexes : les approches

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Section: Methodsmentioning

confidence: 99%

How different is human hair? A critical appraisal of the reported differences in global hair fibre characteristics and properties towards defining a more relevant framework for hair type classification

Daniels¹,

Fraser²,

Westgate³

2022

Intern J of Cosmetic Sci

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show abstract

“…With regards to hair texture, the most common classification is straight, wavy, curly, and sometimes the addition of a “frizzy” category or further subdivisions within these qualitative descriptors (Adhikari et al, 2016; Liu et al, 2018). These qualitative descriptors are inconsistently interpreted and mask the range of variation that exists within tightly curled or “frizzy” hair (Lasisi et al, 2020).…”

Section: Classification and Distortionmentioning

confidence: 99%

“…Yet, what we know about hair biology suggests that variation is more complex than the asserted racial classifications suggest (Adeola et al, 2020;Khumalo, 2007;Lasisi et al, 2016Lasisi et al, , 2020Loussouarn et al, 2007). Various studies of hair fiber curvature and cross-sectional geometry show continuous variation across populations (Fujimoto et al, 2008;Hrdy, 1973;Lasisi et al, 2016;Loussouarn et al, 2007).…”

Section: Objective Variation and Subjective Saliencementioning

confidence: 99%

The constraints of racialization: How classification and valuation hinder scientific research on human variation

Lasisi

2021

American J Phys Anthropol

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Human biological variation has historically been studied through the lens of racialization. Despite a general shift away from the use of overt racial terminologies, the underlying racialized frameworks used to describe and understand human variation still remain. Even in relatively recent anthropological and biomedical work, we can observe clear manifestations of such racial thinking. This paper shows how classification and valuation are two specific processes which facilitate racialization and hinder attempts to move beyond such frameworks. The bias induced by classification distorts descriptions of phenotypic variation in a way that erroneously portrays European populations as more variable than others. Implicit valuation occurs in tandem with classification and produces narratives of superiority/inferiority for certain phenotypic variants without an objective biological basis. The bias of racialization is a persistent impediment stemming from the inheritance of scientific knowledge developed under explicitly racial paradigms. It is also an internalized cognitive distortion cultivated through socialization in a world where racialization is inescapable. Though undeniably challenging, this does not present an insurmountable barrier, and this bias can be mitigated through the critical evaluation of past work, the active inclusion of marginalized perspectives, and the direct confrontation of institutional structures enforcing racialized paradigms.

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High-throughput phenotyping methods for quantifying hair fiber morphology

Cited by 2 publications

References 30 publications

How different is human hair? A critical appraisal of the reported differences in global hair fibre characteristics and properties towards defining a more relevant framework for hair type classification

How different is human hair? A critical appraisal of the reported differences in global hair fibre characteristics and properties towards defining a more relevant framework for hair type classification

The constraints of racialization: How classification and valuation hinder scientific research on human variation

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