By Nichelle Mosley, Founder/ CEO Queen City Beauty Group + Wellness;  United States

Skin color, a visible and variable attribute, is crucial in human biology and evolution. Influenced by geography, UV exposure, and genetics, it goes beyond aesthetics to signify adaptations that have shaped the survival and evolution of human populations. Studying skin color reveals the intricate relationship between humans and their environment, highlighting the delicate balance of natural selection forces that optimize health and reproductive success. This investigation enhances our understanding of human diversity and the broader implications of melanin and skin tone in our species' evolutionary narrative.

The Biological Role of Skin Color
The primary biological function of skin color in humans is to regulate the penetration of ultraviolet radiation (UVR) into the deeper layers of the skin and its circulation.[8] This protective role is crucial as it helps prevent damage from the sun's harmful rays. Historically, the evolution of dark, protective pigmentation and strong tanning abilities has been favored in environments with high UVR, serving as a baseline condition for modern humans.[8] 

Melanin, the pigment responsible for skin color, acts as a natural sunscreen. It protects against the detrimental effects of UVR, such as the depletion of folic acid, which is essential for fetal development, while still allowing for Vitamin D synthesis crucial for bone health.[3] This balance has influenced the evolution of skin color, with darker skin evolving in regions with high UVR to protect against folate degradation, and lighter skin evolving in areas with lower UVR to facilitate Vitamin D production.[3]

Evolution of skin pigmentation has been a complex process influenced by multiple factors including genetic variations, cultural practices, and environmental changes. This adaptability has allowed humans to survive and thrive in a variety of geographical and environmental conditions over millennia.[8] The diversity in skin color observed today is a testament to this evolutionary journey, underscoring the biological and protective roles of skin pigmentation in human
survival.

Evolutionary Adaptations of Skin Color
The evolutionary trajectory of skin color in humans is marked by a significant adaptation to varying ultraviolet (UV) radiation levels across different geographies. Early humans in Africa developed dark skin pigmentation as a natural protective mechanism against the high UV radiation prevalent near the equator. This pigmentation is primarily due to melanin, which acts
as a natural sunscreen  [3]. As human populations migrated out of Africa, they encountered environments with lower UV levels, particularly in higher latitudes. This led to the evolution of lighter skin, which was advantageous for maximizing vitamin D synthesis in conditions of reduced sunlight.[3][1]

Indigenous skin color map

Modern Human Ancestry
Genetic markers provide insights into the migration patterns of early humans and the spread of skin pigmentation traits. Studies of mitochondrial DNA (mtDNA) indicate that while an early exodus from Africa did not contribute to the modern Eurasian gene pool, a later migration around 60,000 years ago left a lasting genetic imprint.[3] This period coincides with low sea levels that may have facilitated migration routes out of Africa.[3]

Gene Variations
The diversity in human skin color is a result of complex genetic variations that respond to environmental pressures. Key genes such as MC1R, OCA2, and TYRP1 play significant roles in melanin production and thus in the determination of skin pigmentation. Variations in these genes are largely influenced by the intensity of UV radiation in different parts of the world, driving the natural selection process that favors skin colors adapted to specific UV exposures.[19] Additionally, gene flow and genetic drift contribute to the spread and variation of skin pigmentation across populations.[19]


Skin Color as a Barrier Function
Melanin serves as a critical protective barrier against ultraviolet radiation (UVR), significantly influencing the synthesis of vitamin D. In individuals with darker skin, the presence of melanin absorbs UVR, which both protects against DNA damage from sun exposure and reduces the production of vitamin D compared to those with lighter skin.[7][3]
This protection is essential in high UVR environments but can lead to vitamin D deficiency in areas with lower sunlight exposure, such as higher latitudes.[10][2] 

Furthermore, melanin's role extends beyond UVR absorption. It acts as a physical barrier that scatters and absorbs UV rays, effectively reducing the penetration of UVR through the epidermis and decreasing the risk of skin cancer. Individuals with darker skin, which contains more eumelanin, are better protected against UV-induced damage compared to those with lighter
skin.[1] 
The skin barrier function is also crucial in preserving folate, which is sensitive to photodegradation by UVR. Darker skin pigmentation, which evolved to protect against folate
degradation, plays a direct role in reproductive health by safeguarding folate reserves essential for fetal development and fertility.

Melanin photoprotection


Global Majority Skin; a new term
In a world that is continually evolving, the "global majority" definition emerges as a pivotal concept, fundamentally challenging traditional notions of ethnicity, diversity, and inclusion. This term, rooted in intersectionality and the understanding of social constructs offers a new lens through which to view the demographic shifts and cultural landscapes that define our global society. Its importance extends beyond mere semantics, providing a framework for discussions around equity and representation in a way that is inclusive and reflective of the world's true diversity.

The exploration of the global majority definition sheds light on its origins, the rationale behind its adoption, and its global reception, including the critiques it faces. Drawing upon concepts of social constructs and intersectionality, “Global Majority” navigates the complex interplay between cultural identities and global demographics, offering insights into how societies might move forward with a more inclusive understanding of humanity.

Historical Context
The term "global majority" was first used in 2003 to challenge the Eurocentric perspective and the normativity of a white majority. This terminology emerged from Rosemary
Campbell-Stephens' work on leadership preparation within the school sector, aiming to recognize the cultural and intellectual contributions of individuals from African, Asian, Indigenous, and dual-heritage backgrounds. [16] [5] It was a strategic shift to empower these groups, who collectively constitute approximately 85 percent of the world's population, by moving away from terms that marginalize or racialize ethnicity.

Current Understanding
Today, the term "People of the Global Majority" (PoGM) encompasses a diverse group including Black, Indigenous, Brown people, and those from various ethnic backgrounds who collectively represent 85% of the global population. This definition serves as a powerful tool against eurocentric ideologies by emphasizing that globally, eurocentric individuals are a minority. This shift in language and perspective not only challenges the traditional racial hierarchy but also empowers the individuals it represents by acknowledging their majority status on a global scale.[6][5]

Rationale for Adopting 'Global Majority Skin'
The adoption of "People of the Global Majority" (PoGM) is a response to the limitations and racial implications of terms like "people of color" which, historically, have centralized whiteness and treated non-white identities as deviations from a white norm.[16]   By using PoGM, the language shifts to empower those it describes, acknowledging their majority status globally and challenging the inherent biases of previous terminologies.

Challenges with Previous Terminologies
Previous terms such as "minorities" or "non-white" inherently position white as the default, perpetuating a racial hierarchy where non-white groups are seen as the 'other'.[4] The term PoGM deconstructs this narrative, removing the comparative reference to whiteness and emphasizing the factual demographic majority of these groups globally. This shift not only challenges the historical context of racial discourse primarily centered around American or Western perspectives but also fosters a more inclusive and accurate representation of global ethnicity and identity.[4]

Conclusion
We have uncovered the profound significance of melanin and skin pigmentation in human survival, adaptation, and social constructs. The interplay between genetics, environmental pressures, and cultural influences has not only shaped the vast spectrum of human skin colors but also highlights the evolutionary advantage of such diversity. By examining the biological mechanisms behind skin color and its evolutionary history, we grasp the complex narrative of human adaptation to varied ecological niches and the ongoing impact of cultural practices and dietary shifts on skin pigmentation.

The insights garnered from studying the evolutionary adaptations and implications of skin color extend beyond mere academic interest; they underscore the importance of appreciating and understanding human diversity in all its forms. As we consider the protective roles of melanin, the influence of UV radiation on skin pigmentation, and the cultural determinants of skin color, we are reminded of the intricate connections between our biological heritage and the environments we inhabit. Future research into skin pigmentation and its evolutionary background promises not only to enrich our comprehension of human biology but also to foster a deeper respect for the richness of human diversity and the shared genetics that unites us all.

References used in this article:

[1] - https://w w w.psu.edu/impact/stor y/the-evolution-of-skin-color/  [2] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC8359960/ 
[3] - http://humanorigins.si.edu/evidence/genetics/human-skin-color-variation
[4]  https://regenerative.medium.com/im-embracing-the-term-people-of-the-global-majority-abd1c 1251241 
[5] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC8247429/ 
[6] -  https://w w w.leedsbeckett.ac.uk/-/media/files/schools/school-of-education/final-leeds-beckett- 1102-global-majority.pdf 
[7] - https://w w w.biointeractive.org /sites/default/files/SkinColor-Educator-film.pdf  [8] - https://royalsocietypublishing.org /doi/10.1098/rstb.2016.0349
[9] - https://karger.com/spp/article/35/2/65/826910/Influence-of-Ethnicities-and-Skin-Color-Variations 
[10] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC10083917/ [11] - https://w w w.palomar.edu/anthro/adapt/adapt_4.htm
[12] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC3267121/  [13] - https://w w w.ewg.org /news-insights/news/2022/05/what-effect-do-melanin-and-sunscreen-have-v 
[14] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC5946242/  sunscreen-have-v
[15] - https://pubmed.ncbi.nlm.nih. gov/24134867/ 
[16] -https://britthaw thorne.com/blog /people-global-majority/ 
[17] - https://journals.physiology.org /doi/10.1152/ajpregu.00136.2019 
[18] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC3795437/
[19] - https://w w w.sciencedaily.com/releases/2017/10/171012143324.htm  [20] - https://pubmed.ncbi.nlm.nih. gov/34515229/ 
[21] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC5986434/  [22] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC2671032/  [23] - https://w w w.ncbi.nlm.nih. gov/pmc/articles/PMC3709783/  [24] - https://w w w.pnas.org /doi/10.1073/pnas.0914628107

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