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Pokorný Š, Pavlovič O, Kleisner K. Sexual Dimorphism: The Interrelation of Shape and Color. ARCHIVES OF SEXUAL BEHAVIOR 2024; 53:3255-3265. [PMID: 38944665 PMCID: PMC11335828 DOI: 10.1007/s10508-024-02918-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 05/27/2024] [Accepted: 05/28/2024] [Indexed: 07/01/2024]
Abstract
Sex-typicality displayed as sexual dimorphism of the human face is a key feature enabling sex recognition. It is also believed to be a cue for perceiving biological quality and it plays an important role in the perception of attractiveness. Sexual dimorphism of human faces has two main components: sexual shape dimorphism of various facial features and sexual color dimorphism, generally manifested as dimorphism of skin luminance, where men tend to be darker than women. However, very little is known about the mutual relationship of these two facets. We explored the interconnection between the dimorphism of face shape and dimorphism of face color in three visually distinct populations (Cameroonian, Czech, and Vietnamese). Our results indicated that populations which showed a significant dimorphism in skin luminance (Cameroon, Vietnam) had low levels of sexual shape dimorphism, while a population with higher levels of sexual shape dimorphism (Czech Republic) did not exhibit a significant dimorphism of skin luminance. These findings suggest a possible compensatory mechanism between various domains of sexual dimorphism in populations differing in the levels of shape and color dimorphism.
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Affiliation(s)
- Šimon Pokorný
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Albertov 6, 128 00, Prague, Czech Republic.
| | - Ondřej Pavlovič
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Albertov 6, 128 00, Prague, Czech Republic
| | - Karel Kleisner
- Department of Philosophy and History of Science, Faculty of Science, Charles University, Albertov 6, 128 00, Prague, Czech Republic
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Yu Z, Flament F, Jiang R, Houghton J, Kroely C, Cabut N, Haykal D, Sehgal C, Jablonski NG, Jean A, Aarabi P. The relevance and accuracy of an AI algorithm-based descriptor on 23 facial attributes in a diverse female US population. Skin Res Technol 2024; 30:e13690. [PMID: 38716749 PMCID: PMC11077572 DOI: 10.1111/srt.13690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 03/18/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND The response of AI in situations that mimic real life scenarios is poorly explored in populations of high diversity. OBJECTIVE To assess the accuracy and validate the relevance of an automated, algorithm-based analysis geared toward facial attributes devoted to the adornment routines of women. METHODS In a cross-sectional study, two diversified groups presenting similar distributions such as age, ancestry, skin phototype, and geographical location was created from the selfie images of 1041 female in a US population. 521 images were analyzed as part of a new training dataset aimed to improve the original algorithm and 520 were aimed to validate the performance of the AI. From a total 23 facial attributes (16 continuous and 7 categorical), all images were analyzed by 24 make-up experts and by the automated descriptor tool. RESULTS For all facial attributes, the new and the original automated tool both surpassed the grading of the experts on a diverse population of women. For the 16 continuous attributes, the gradings obtained by the new system strongly correlated with the assessment made by make-up experts (r ≥ 0.80; p < 0.0001) and supported by a low error rate. For the seven categorical attributes, the overall accuracy of the AI-facial descriptor was improved via enrichment of the training dataset. However, some weaker performance in spotting specific facial attributes were noted. CONCLUSION In conclusion, the AI-automatic facial descriptor tool was deemed accurate for analysis of facial attributes for diverse women although some skin complexion, eye color, and hair features required some further finetuning.
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Affiliation(s)
- Zhi Yu
- Modiface – A L'Oréal Group CompanyTorontoCanada
| | | | | | | | | | | | | | | | - Nina G Jablonski
- Department of AnthropologyThe Pennsylvania State University, University ParkPennsylvaniaUSA
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Ma Y, Tan Y, Hu Y, Pu W, Xu J, Jin L, Wang J. Quantitative Assessment of Ultraviolet-Induced Erythema and Tanning Responses in the Han Chinese Population. PHENOMICS (CHAM, SWITZERLAND) 2024; 4:138-145. [PMID: 38884062 PMCID: PMC11169260 DOI: 10.1007/s43657-023-00105-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 03/07/2023] [Accepted: 03/15/2023] [Indexed: 06/18/2024]
Abstract
Ultraviolet radiation (UVR) can induce erythema and tanning responses with strong diversity within and between populations, but there were no precise method for evaluating the variation in these responses. In this study, we assessed the time course of ultraviolet (UV)-induced responses based on the erythema index (EI) and melanin index (MI) over 14 consecutive days in a pilot cohort study (N = 31). From safety evaluations, we found that no skin blisters occurred at a UV dosage of 45 mJ/cm2, but there were significant skin reactions. Regardless of UV dosage, the measurements and variances of EI peaked on day 1 after UV irradiation, and those of MI peaked on day 7. Dose-response curves, including erythema dose-response (EDR) and melanin dose-response (MDR), could measure UV-induced phenotypes sensitively but more laboriously. As an alternative, we directly represented the UV-induced erythema and tanning responses using the erythema increment (ΔE) and melanin increment (ΔM). We found that ΔE and ΔM at 45 mJ/cm2 significantly correlated with erythema dose-response (EDR) (R 2 > 0.9) and melanin dose-response (MDR) (R 2 > 0.9), respectively. Therefore, ΔE and ΔM on day 1 and day 7 after UV irradiation at a dosage of 45 mJ/cm2 might be ideal alternative measures for assessing individual erythema and tanning responses. Then, a second cohort (N = 664) was recruited to validate the UV-induced phenotypes, and, as expected, the results of the two cohorts were in agreement. Therefore, we developed a simplified and precise method to quantify the UV-induced erythema response and tanning ability for the Han Chinese population. Supplementary Information The online version contains supplementary material available at 10.1007/s43657-023-00105-1.
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Affiliation(s)
- Yanyun Ma
- State Key Laboratory of Genetic Engineering, School of Life Sciences, and Human Phenome Institute, Fudan University, Shanghai, 201203 China
- Six-Sector Industrial Research Institute, Fudan University, Shanghai, 200433 China
- Research Unit of Dissecting the Population Genetics and Developing New Technologies for Treatment and Prevention of Skin Phenotypes and Dermatological Diseases, Chinese Academy of Medical Sciences (2019RU058), Shanghai, 200438 China
| | - Yimei Tan
- State Key Laboratory of Genetic Engineering, School of Life Sciences, and Human Phenome Institute, Fudan University, Shanghai, 201203 China
- Shanghai Skin Disease Hospital, Shanghai, 200443 China
| | - Yue Hu
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, 200040 China
| | - Weilin Pu
- MOE Key Laboratory of Contemporary Anthropology, School of Life Science, Collaborative Innovation Center for Genetics and Development, Fudan University, Shanghai, 200438 China
- Research Unit of Dissecting the Population Genetics and Developing New Technologies for Treatment and Prevention of Skin Phenotypes and Dermatological Diseases, Chinese Academy of Medical Sciences (2019RU058), Shanghai, 200438 China
| | - Jinhua Xu
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, 200040 China
| | - Li Jin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, and Human Phenome Institute, Fudan University, Shanghai, 201203 China
- Six-Sector Industrial Research Institute, Fudan University, Shanghai, 200433 China
- Research Unit of Dissecting the Population Genetics and Developing New Technologies for Treatment and Prevention of Skin Phenotypes and Dermatological Diseases, Chinese Academy of Medical Sciences (2019RU058), Shanghai, 200438 China
| | - Jiucun Wang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, and Human Phenome Institute, Fudan University, Shanghai, 201203 China
- Six-Sector Industrial Research Institute, Fudan University, Shanghai, 200433 China
- Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, 200040 China
- Research Unit of Dissecting the Population Genetics and Developing New Technologies for Treatment and Prevention of Skin Phenotypes and Dermatological Diseases, Chinese Academy of Medical Sciences (2019RU058), Shanghai, 200438 China
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Flament F, Jiang R, Houghton J, Zhang Y, Kroely C, Jablonski NG, Jean A, Clarke J, Steeg J, Sehgal C, McParland J, Delaunay C, Passeron T. Accuracy and clinical relevance of an automated, algorithm-based analysis of facial signs from selfie images of women in the United States of various ages, ancestries and phototypes: A cross-sectional observational study. J Eur Acad Dermatol Venereol 2023; 37:176-183. [PMID: 35986708 PMCID: PMC10087370 DOI: 10.1111/jdv.18541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 07/27/2022] [Indexed: 12/15/2022]
Abstract
BACKGROUND Real-life validation is necessary to ensure our artificial intelligence (AI) skin diagnostic tool is inclusive across a diverse and representative US population of various ages, ancestries and skin phototypes. OBJECTIVES To explore the relevance and accuracy of an automated, algorithm-based analysis of facial signs in representative women of different ancestries, ages and phototypes, living in the same country. METHODS In a cross-sectional study of selfie images of 1041 US women, algorithm-based analyses of seven facial signs were automatically graded by an AI-based algorithm and by 50 US dermatologists of various profiles (age, gender, ancestry, geographical location). For automated analysis and dermatologist assessment, the same referential skin atlas was used to standardize the grading scales. The average values and their variability were compared with respect to age, ancestry and phototype. RESULTS For five signs, the grading obtained by the automated system were strongly correlated with dermatologists' assessments (r ≥ 0.75); cheek skin pores were moderately correlated (r = 0.63) and pigmentation signs, especially for the darkest skin tones, were weakly correlated (r = 0.40) to the dermatologist assessments. Age and ancestry had no effect on the correlations. In many cases, the automated system performed better than the dermatologist-assessed clinical grading due to 0.3-0.5 grading unit differences among the dermatologist panel that were not related to any individual characteristic (e.g. gender, age, ancestry, location). The use of phototypes, as discontinuous categorical variables, is likely a limiting factor in the assessments of grading, whether obtained by automated analysis or clinical assessment of the images. CONCLUSIONS The AI-based automatic procedure is accurate and clinically relevant for analysing facial signs in a diverse and inclusive population of US women, as confirmed by a diverse panel of dermatologists, although skin tone requires further improvement.
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Affiliation(s)
| | - Ruowei Jiang
- ModiFace - A L'Oréal Group Company, Toronto, Ontario, Canada
| | - Jeff Houghton
- ModiFace - A L'Oréal Group Company, Toronto, Ontario, Canada
| | - Yuze Zhang
- ModiFace - A L'Oréal Group Company, Toronto, Ontario, Canada
| | | | - Nina G Jablonski
- Department of Anthropology, The Pennsylvania State University, University Park, State College, Pennsylvania, USA
| | | | - Jeffrey Clarke
- Evaluative Criteria Incorporated, Tarrytown, New York, USA
| | - Jason Steeg
- Evaluative Criteria Incorporated, Tarrytown, New York, USA
| | | | | | | | - Thierry Passeron
- Department of Dermatology, Université Côte d'Azur, CHU Nice, Nice, France.,Université Côte d'Azur, INSERM, U1065, C3M, Nice, France
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Uto T, Ohta T, Nakayama E, Nakagawa M, Hatada M, Shoyama Y. Bioassay-guided Fractionation of Clove Buds Extract Identifies Eugenol as Potent Melanogenic Inducer in Melanoma Cells. J Oleo Sci 2022; 71:1403-1412. [PMID: 36047244 DOI: 10.5650/jos.ess22157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Clove, a dried flower buds of Syzygium aromaticum, is used in traditional medicine, for culinary purposes, and in essential oil production. In our preliminary screening of crude drugs used in Japanese Kampo formulas, a methanol (MeOH) extract of clove buds was found to exhibit a melanin induction. To date, the effects of clove buds or their constituents on the activation of melanogenesis remain unclear. Thus, this study aimed to isolate active compounds from the MeOH extract of clove buds associated with melanin synthesis in melanoma cells and to investigate the molecular mechanism involved. The MeOH extract of clove buds increased melanin content in murine B16-F1 melanoma cells. To identify the active compounds responsible for melanin induction, the MeOH extract was suspended in water and successively partitioned using hexane, ethyl acetate (EtOAc), and n-butanol (n-BuOH). Comparative analysis revealed that the EtOAc fraction induced melanin synthesis. Bioassay-guided separation of the EtOAc fraction isolated three compounds including eugenol. The analysis of structure-activity relationships of eugenol and structurally related compounds indicated that eugenol was the most potent melanin inducer among the 11 compounds, and that a hydroxyl group at C-1 and a methoxy group at C-2 may contribute to melanin induction. Eugenol induced melanin synthesis in human HMV-II melanoma cells as well as in B16-F1 cells. Further analysis indicated that eugenol may invoke intracellular tyrosinase activity and expression of tyrosinase, tyrosinaserelated protein (TRP)-1, TRP-2, and microphthalmia-associated transcription factor (MITF). These results suggest that eugenol enhances melanin synthesis by upregulating the expression of MITF and subsequent expression of melanogenic enzymes, and that it may be a potent therapeutic agent for hypopigmentation.
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Affiliation(s)
- Takuhiro Uto
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Tomoe Ohta
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Eri Nakayama
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Mina Nakagawa
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Maki Hatada
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Nagasaki International University
| | - Yukihiro Shoyama
- Department of Pharmacognosy, Faculty of Pharmaceutical Sciences, Nagasaki International University
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Dabas P, Jain S, Khajuria H, Nayak BP. Forensic DNA phenotyping: Inferring phenotypic traits from crime scene DNA. J Forensic Leg Med 2022; 88:102351. [DOI: 10.1016/j.jflm.2022.102351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 03/01/2022] [Accepted: 04/04/2022] [Indexed: 10/18/2022]
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Galliano A, Guerin M, Lambert V, Favrot I, Seneca D, Lequeux F, Flament F, Sleurs A, Foster B, Phung E, Lee KM, Houghton J. Virtual approach of the aesthetical fit between hair colours and skin tones in women of different ethnical origin backgrounds. Skin Res Technol 2022; 28:455-464. [PMID: 35261091 PMCID: PMC9907600 DOI: 10.1111/srt.13146] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Accepted: 01/17/2022] [Indexed: 02/06/2023]
Abstract
OBJECTIVE To determine the aesthetical accordance between a given skin tone and the 11 possible colours of head hairs, covered by a marketed hair colouration product. MATERIAL AND METHODS The photographs of professional top models, representing several ancestries (non-Hispanic European and Euro-American, East Asian, Hispanic Euro-American, and African-American ancestries), were used to virtually modify skin tones (from light, medium to dark) and hair colour by an artificial intelligence (AI)-based algorithm. Hence, 117 modified photographs were then assessed by five local panels of about 60 women each (one in China, one in France and three in US). The same questionnaire was given to the panels, written in their own language, asking which and how both skin tones and hair colours fit preferentially (or not appreciated), asking in addition the reasons of their choices, using fixed wordings. RESULTS Answers from the five panels differed according to origin or cultural aspects, although some agreements were found among both non-Hispanic European and Euro-American groups. The Hispanic American panel in US globally much appreciated darker hair tones (HTs). Two panels (East Asian in China and African American in US) and part of non-Hispanic European panel in France declared appreciating all HTs, almost irrespective with the skin tone (light, medium and dark). This surprising result is very likely caused by gradings (in %) that differ by too low values, making the establishment of a decisive or significant assessment. By nature highly subjective (culturally and/or fashion driven), the assessments should be more viewed as trends, an unavoidable limit of the present virtual approach. The latter offers nevertheless a full respect of ethical rules as such objective could hardly be conducted in vivo: applying 10 or 11 hair colourations on the same individual is an unthinkable option. CONCLUSION The virtual approach developed in the present study that mixes two major facial coloured phenotypes seems at the crossroad of both genetic backgrounds and the secular desire of a modified appearance. Nonetheless, this methodology could afford, at the individual level in total confidentiality, a great help to subjects exposed to some facial skin disorders or afflictions.
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Affiliation(s)
- Anthony Galliano
- L'Oréal Research and Innovation, Centre Charles Zviak, Saint-Ouen, France
| | - Myriam Guerin
- L'Oréal Research and Innovation, Centre Charles Zviak, Saint-Ouen, France
| | - Valerie Lambert
- L'Oréal Research and Innovation, Centre Charles Zviak, Saint-Ouen, France
| | - Ioanna Favrot
- L'Oréal Research and Innovation, Centre Charles Zviak, Saint-Ouen, France
| | - David Seneca
- L'Oréal Research and Innovation, Centre Charles Zviak, Saint-Ouen, France
| | - Fabien Lequeux
- L'Oréal Research and Innovation, Centre Charles Zviak, Saint-Ouen, France
| | - Frédéric Flament
- L'Oréal Research and Innovation, Centre Charles Zviak, Saint-Ouen, France
| | - Anna Sleurs
- L'Oréal Paris, Centre Eugene Schueller, Clichy, France
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Jablonski NG. The evolution of human skin pigmentation involved the interactions of genetic, environmental, and cultural variables. Pigment Cell Melanoma Res 2021; 34:707-729. [PMID: 33825328 PMCID: PMC8359960 DOI: 10.1111/pcmr.12976] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2021] [Revised: 03/30/2021] [Accepted: 04/03/2021] [Indexed: 12/12/2022]
Abstract
The primary biological role of human skin pigmentation is as a mediator of penetration of ultraviolet radiation (UVR) into the deep layers of skin and the cutaneous circulation. Since the origin of Homo sapiens, dark, protective constitutive pigmentation and strong tanning abilities have been favored under conditions of high UVR and represent the baseline condition for modern humans. The evolution of partly depigmented skin and variable tanning abilities has occurred multiple times in prehistory, as populations have dispersed into environments with lower and more seasonal UVR regimes, with unique complements of genes and cultural practices. The evolution of extremes of dark pigmentation and depigmentation has been rare and occurred only under conditions of extremely high or low environmental UVR, promoted by positive selection on variant pigmentation genes followed by limited gene flow. Over time, the evolution of human skin pigmentation has been influenced by the nature and course of human dispersals and modifications of cultural practices, which have modified the nature and actions of skin pigmentation genes. Throughout most of prehistory and history, the evolution of human skin pigmentation has been a contingent and non-deterministic process.
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Affiliation(s)
- Nina G. Jablonski
- Department of AnthropologyThe Pennsylvania State UniversityUniversity ParkPAUSA
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Bourhim T, Villareal MO, Couderc F, Hafidi A, Isoda H, Gadhi C. Melanogenesis Promoting Effect, Antioxidant Activity, and UPLC-ESI-HRMS Characterization of Phenolic Compounds of Argan Leaves Extract. Molecules 2021; 26:E371. [PMID: 33445748 PMCID: PMC7828169 DOI: 10.3390/molecules26020371] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/06/2021] [Accepted: 01/09/2021] [Indexed: 11/17/2022] Open
Abstract
The use of natural products for the regulation of skin pigmentation is gaining popularity. In the present study, we evaluated the effect of argan leaves extract (ALE) on melanogenesis in B16 melanoma cells, determined its antioxidant activity, then quantified and identified its phenolic components. B16 cells were treated with various concentrations of ALE, then the cell viability and proliferation were assessed using MTT assay while the melanin content was determined using spectrophotometric methods. The expression level of tyrosinase (TYR), tyrosinase related protein-1 (TRP-1) and dopachrome tautomerase (DCT) was evaluated by Western blotting. The antioxidant activity of ALE was investigated using four different assays while UPLC-ESI-HRMS analysis was used to characterize the ALE phenolic profile. Fourteen phenolic compounds were identified, of which six are reported for the first time to be present in ALE. ALE treatment increases the melanin content of B16 cells in a dose-dependent manner without cytotoxicity. This was revealed by the observed ALE-increased expression level of TYR, DCT, and TRP-1. These bioactivities may be mainly attributed to its high flavonoids content. Argan leaves have the potential for use as a treatment for hypopigmentation disorders and as a bioactive component of cosmetic products that aim to increase pigmentation.
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Affiliation(s)
- Thouria Bourhim
- Faculty of Sciences Semlalia, Cadi Ayyad University, Avenue Prince Moulay Abdellah, BP 2390, 40000 Marrakesh, Morocco; (T.B.); (A.H.)
| | - Myra O. Villareal
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, Tennodai 1-1-1, Tsukuba City 305-8572, Japan;
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba City 305-8572, Japan
| | - François Couderc
- UMR CNRS 5623 (National Center for Scientific Research), Paul Sabatier University, 118 Route de Narbonne, F-31062 Toulouse, France;
| | - Abdellatif Hafidi
- Faculty of Sciences Semlalia, Cadi Ayyad University, Avenue Prince Moulay Abdellah, BP 2390, 40000 Marrakesh, Morocco; (T.B.); (A.H.)
| | - Hiroko Isoda
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, Tennodai 1-1-1, Tsukuba City 305-8572, Japan;
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tennodai 1-1-1, Tsukuba City 305-8572, Japan
| | - Chemseddoha Gadhi
- Faculty of Sciences Semlalia, Cadi Ayyad University, Avenue Prince Moulay Abdellah, BP 2390, 40000 Marrakesh, Morocco; (T.B.); (A.H.)
- Alliance for Research on the Mediterranean and North Africa (ARENA), University of Tsukuba, Tennodai 1-1-1, Tsukuba City 305-8572, Japan;
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Missaggia BO, Reales G, Cybis GB, Hünemeier T, Bortolini MC. Adaptation and co-adaptation of skin pigmentation and vitamin D genes in native Americans. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2020; 184:1060-1077. [PMID: 33325159 DOI: 10.1002/ajmg.c.31873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/23/2020] [Accepted: 12/02/2020] [Indexed: 11/06/2022]
Abstract
We carried out an exhaustive review regarding human skin color variation and how much it may be related to vitamin D metabolism and other photosensitive molecules. We discuss evolutionary contexts that modulate this variability and hypotheses postulated to explain them; for example, a small amount of melanin in the skin facilitates vitamin D production, making it advantageous to have fair skin in an environment with little radiation incidence. In contrast, more melanin protects folate from degradation in an environment with a high incidence of radiation. Some Native American populations have a skin color at odds with what would be expected for the amount of radiation in the environment in which they live, a finding challenging the so-called "vitamin D-folate hypothesis." Since food is also a source of vitamin D, dietary habits should also be considered. Here we argue that a gene network approach provides tools to explain this phenomenon since it indicates potential alleles co-evolving in a compensatory way. We identified alleles of the vitamin D metabolism and pigmentation pathways segregated together, but in different proportions, in agriculturalists and hunter-gatherers. Finally, we highlight how an evolutionary approach can be useful to understand current topics of medical interest.
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Affiliation(s)
- Bruna Oliveira Missaggia
- Genetics Departament, Biosciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Guillermo Reales
- Genetics Departament, Biosciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Gabriela B Cybis
- Statistics Department, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Tábita Hünemeier
- Department of Genetics and Evolutionary Biology, Biosciences Institute, Universidade de São Paulo, São Paulo, SP, Brazil
| | - Maria Cátira Bortolini
- Genetics Departament, Biosciences Institute, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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Werren EA, Garcia O, Bigham AW. Identifying adaptive alleles in the human genome: from selection mapping to functional validation. Hum Genet 2020; 140:241-276. [PMID: 32728809 DOI: 10.1007/s00439-020-02206-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Accepted: 07/07/2020] [Indexed: 12/19/2022]
Abstract
The suite of phenotypic diversity across geographically distributed human populations is the outcome of genetic drift, gene flow, and natural selection throughout human evolution. Human genetic variation underlying local biological adaptations to selective pressures is incompletely characterized. With the emergence of population genetics modeling of large-scale genomic data derived from diverse populations, scientists are able to map signatures of natural selection in the genome in a process known as selection mapping. Inferred selection signals further can be used to identify candidate functional alleles that underlie putative adaptive phenotypes. Phenotypic association, fine mapping, and functional experiments facilitate the identification of candidate adaptive alleles. Functional investigation of candidate adaptive variation using novel techniques in molecular biology is slowly beginning to unravel how selection signals translate to changes in biology that underlie the phenotypic spectrum of our species. In addition to informing evolutionary hypotheses of adaptation, the discovery and functional annotation of adaptive alleles also may be of clinical significance. While selection mapping efforts in non-European populations are growing, there remains a stark under-representation of diverse human populations in current public genomic databases, of both clinical and non-clinical cohorts. This lack of inclusion limits the study of human biological variation. Identifying and functionally validating candidate adaptive alleles in more global populations is necessary for understanding basic human biology and human disease.
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Affiliation(s)
- Elizabeth A Werren
- Department of Human Genetics, The University of Michigan, Ann Arbor, MI, USA
- Department of Anthropology, The University of Michigan, Ann Arbor, MI, USA
| | - Obed Garcia
- Department of Anthropology, The University of Michigan, Ann Arbor, MI, USA
| | - Abigail W Bigham
- Department of Anthropology, University of California Los Angeles, 341 Haines Hall, Los Angeles, CA, 90095, USA.
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Casella A, Long C, Zhou J, Lai M, O’Lear L, Caplan I, Levine MA, Roizen JD. Differential Frequency of CYP2R1 Variants Across Populations Reveals Pathway Selection for Vitamin D Homeostasis. J Clin Endocrinol Metab 2020; 105:dgaa056. [PMID: 32115644 PMCID: PMC7096315 DOI: 10.1210/clinem/dgaa056] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 02/05/2020] [Indexed: 12/31/2022]
Abstract
CONTEXT Normal vitamin D homeostasis is necessary to ensure optimal mineral metabolism. Dietary insufficiency of vitamin D and the lack of sunlight each have well understood roles in vitamin D deficiency; however, the extent to which common genetic variations in vitamin D metabolizing enzymes contribute to alterations in vitamin D homeostasis remains uncertain. OBJECTIVE To examine the possibility that common coding variation in vitamin D metabolizing enzymes alters vitamin D homeostasis we determined the effect of 44 nonsynonymous polymorphisms in CYP2R1, the vitamin D 25-hydroxylase, on enzyme function. RESULTS Twenty-one of these polymorphisms decreased activity, while 2 variants increased activity. The frequency of CYP2R1 alleles with decreased 25-hydroxylase activity is 3 in every 1000 Caucasians and 7 in every 1000 African Americans. In populations where exposure to sunlight is high, alleles with decreased function occur at a frequency as high as 8%. The pattern of selected variation as compared to nonselected variation is consistent with it being the result of positive selection for nonfunctional alleles closer to the equator. To examine this possibility, we examined the variation pattern in another protein in the vitamin D pathway, the vitamin D binding protein (GC protein). The pattern of selected variation in the GC protein as compared to nonselected variation is also consistent with it being the result of positive selection for nonfunctional alleles closer to the equator. CONCLUSIONS CYP2R1 polymorphisms have important effects on vitamin D homeostasis, and the geographic variability of CYP2R1 alleles represents an adaptation to differential exposures to UVB irradiation from sunlight.
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Affiliation(s)
- Alex Casella
- Division of Endocrinology and Diabetes, Department of Pediatrics, Children’s Hospital of Pennsylvania, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Caela Long
- Division of Endocrinology and Diabetes, Department of Pediatrics, Children’s Hospital of Pennsylvania, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Jingman Zhou
- Spark Therapeutics, Inc, Philadelphia, Pennsylvania
| | - Meizan Lai
- Division of Endocrinology and Diabetes, Department of Pediatrics, Children’s Hospital of Pennsylvania, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Lauren O’Lear
- Division of Endocrinology and Diabetes, Department of Pediatrics, Children’s Hospital of Pennsylvania, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Ilana Caplan
- Division of Endocrinology and Diabetes, Department of Pediatrics, Children’s Hospital of Pennsylvania, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Michael A Levine
- Division of Endocrinology and Diabetes, Department of Pediatrics, Children’s Hospital of Pennsylvania, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Jeffrey D Roizen
- Division of Endocrinology and Diabetes, Department of Pediatrics, Children’s Hospital of Pennsylvania, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
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Vieth R. Weaker bones and white skin as adaptions to improve anthropological "fitness" for northern environments. Osteoporos Int 2020; 31:617-624. [PMID: 31696275 PMCID: PMC7075826 DOI: 10.1007/s00198-019-05167-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Accepted: 09/11/2019] [Indexed: 01/12/2023]
Abstract
The vitamin D paradox relates to the lower risk of osteoporosis in people of sub-Saharan African ancestry (Blacks) compared with people of European ancestry (Whites). The paradox implies that for bone health, Blacks require less vitamin D and calcium than Whites do. Why should populations that migrated northward out of Africa have ended up needing more vitamin D than tropical Blacks? Human skin color became lighter away from the tropics to permit greater skin penetration of the UVB light that generates vitamin D. Lack of vitamin D impairs intestinal calcium absorption and limits the amount of calcium that can deposit into the protein matrix of bone, causing rickets or osteomalacia. These can cause cephalopelvic disproportion and death in childbirth. Whiter skin was more fit for reproduction in UV-light restricted environments, but natural selection was also driven by the phenotype of bone per se. Bone formation starts with the deposition of bone-matrix proteins. Mineralization of the matrix happens more slowly, and it stiffens bone. If vitamin D and/or calcium supplies are marginal, larger bones will not be as fully mineralized as smaller bones. For the same amount of mineral, unmineralized or partially mineralized bone is more easily deformed than fully mineralized bone. The evidence leads to the hypothesis that to minimize the soft bone that causes pelvic deformation, a decrease in amount of bone, along with more rapid mineralization of osteoid improved reproductive fitness in Whites. Adaptation of bone biology for reproductive fitness in response to the environmental stress of limited availability of vitamin D and calcium came at the cost of greater risk of osteoporosis later in life.
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Affiliation(s)
- R Vieth
- Department of Laboratory Medicine and Pathobiology, and Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Medical Sciences Building, 5th Floor, Room 5253A 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
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Vieth R. The Paleolithic Nutrition Model in Relation to Ultraviolet Light and Vitamin D. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1268:409-419. [PMID: 32918231 DOI: 10.1007/978-3-030-46227-7_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The biology of every species has been optimized for life in the environment in which that species evolved. Humans originated in the tropics, and while some natural selection took place in response to behaviors and environments that decreased exposure to ultraviolet light, there has never been a species-wide biological accommodation. Paleolithic nutrition advocates argue that risk of disease is higher because modern diets differ from what was consumed by early humans. Early humans were the naked ape living in the tropics, exposed to high levels of ultraviolet light and vitamin D nutrition (serum 25-hydroxyvitamin D; 25(OH)D) averaging 115 nmol/L, as compared to today's population averages that are well below 70 nmol/L. Natural selection from an available gene pool cannot compensate fully to an environmental change away from the one within which the species originally evolved. Vitamin D nutrition remains a contentious area. The epidemiological evidence consistently relates lower 25(OH)D to higher disease risk. However, evidence from double-blind clinical trials looking at preventing new disease in healthy volunteers has been disappointing. But such negative trials have been the case for all nutrients except for folic acid which lowers risk of spina bifida. The Paleolithic nutrition model is based on fundamental biological concepts, but it has overlooked the environmental effects of ultraviolet light and vitamin D nutrition. This paper presents evolutionary and Paleolithic aspects of ultraviolet light and vitamin D with the aim to support pertinent research and, ultimately, public policy regarding nutrition and light exposure.
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Affiliation(s)
- Reinhold Vieth
- Department of Laboratory Medicine and Pathobiology, and Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
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15
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Flament F, Velleman D, Yamamoto S, Nicolas A, Udodaira K, Yamamoto S, Morimoto C, Belkebla S, Negre C, Delaunay C. Clinical impacts of sun exposures on the faces and hands of Japanese women of different ages. Int J Cosmet Sci 2019; 41:425-436. [DOI: 10.1111/ics.12555] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/14/2019] [Indexed: 01/16/2023]
Affiliation(s)
- F. Flament
- L’Oréal Research and Innovation 9, Rue Pierre Dreyfus 93400 Clichy France
| | - D. Velleman
- L’Oréal Research and Innovation 3-2-1 Takatsu-ku Sakado213 012 Kawasaki-Shi Kanagawa Japan
| | - S. Yamamoto
- L’Oréal Research and Innovation 3-2-1 Takatsu-ku Sakado213 012 Kawasaki-Shi Kanagawa Japan
| | - A. Nicolas
- L’Oréal Research and Innovation 3-2-1 Takatsu-ku Sakado213 012 Kawasaki-Shi Kanagawa Japan
| | - K. Udodaira
- L’Oréal Research and Innovation 3-2-1 Takatsu-ku Sakado213 012 Kawasaki-Shi Kanagawa Japan
| | - S. Yamamoto
- L’Oréal Research and Innovation 3-2-1 Takatsu-ku Sakado213 012 Kawasaki-Shi Kanagawa Japan
| | - C. Morimoto
- L’Oréal Research and Innovation 3-2-1 Takatsu-ku Sakado213 012 Kawasaki-Shi Kanagawa Japan
| | - S. Belkebla
- L’Oréal Research and Innovation 9, Rue Pierre Dreyfus 93400 Clichy France
| | - C. Negre
- L’Oréal 62, Quai Charles Pasqua 92300 Levallois‐Perret France
| | - C. Delaunay
- L’Oréal Research and Innovation 3-2-1 Takatsu-ku Sakado213 012 Kawasaki-Shi Kanagawa Japan
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16
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Carrito ML, Semin GR. When we don't know what we know - Sex and skin color. Cognition 2019; 191:103972. [PMID: 31228668 DOI: 10.1016/j.cognition.2019.05.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 05/13/2019] [Accepted: 05/14/2019] [Indexed: 11/27/2022]
Abstract
In 3 experiments, we examine how the abstract category of gender, grounded by the lightness-darkness dimension, derived from the universal sexual dimorphism of skin color, is represented and how such representations lead to visual accentuation processes, i.e. polarization of differences between male and female faces. In the first two experiments, we show that irrespective of whether grayscale male and female faces are presented sequentially or jointly, female faces are judged to be lighter than male faces when participants are asked to indicate the level of lightness of the faces. This pattern was found for the majority of participants who explicitly stated that men and women do not differ in skin color. The third experiment was designed to examine the cognitive consequences of what people implicitly 'know' with a perceptual accentuation study. Participants were provided with male and female faces of equal skin color. Subsequently, in a memory recall task, they were asked to select, from a row of several faces varying in skin color, the original face. They chose, as predicted, lighter versions of faces for females compared to the male faces. This research reveals that the evolutionarily based sexual dimorphism in skin color implicitly grounds gender categories and shapes implicit visual accentuation processes.
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Affiliation(s)
- Mariana L Carrito
- Centre for Psychology at University of Porto, Faculty of Psychology and Education Sciences - University of Porto, Rua Alfredo Allen, 4200-135 Porto, Portugal.
| | - Gün R Semin
- William James Center for Research, ISPA - Instituto Universitário, Rua Jardim do Tabaco 41, 1149-041 Lisboa, Portugal; Faculty of Social and Behavioral Sciences, Utrecht University, 3584 CS Utrecht, the Netherlands.
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17
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Wide coverage of the body surface by melanocyte-mediated skin pigmentation. Dev Biol 2019; 449:83-89. [DOI: 10.1016/j.ydbio.2018.04.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 12/20/2022]
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18
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Veselka B, Brickley MB, D'Ortenzio L, Kahlon B, Hoogland MLP, Waters‐Rist AL. Micro-CT assessment of dental mineralization defects indicative of vitamin D deficiency in two 17th-19th century Dutch communities. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2019; 169:122-131. [PMID: 30882907 PMCID: PMC6593783 DOI: 10.1002/ajpa.23819] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/25/2019] [Accepted: 02/25/2019] [Indexed: 12/25/2022]
Abstract
OBJECTIVES This study investigates vitamin D deficiency patterns in individuals from birth to the beginning of adolescence. Microscopic computed tomography (micro-CT) evaluation of interglobular dentine (IGD) in teeth provides information on the age of disease onset and the number of deficient periods per individual, which will increase our understanding of factors influencing vitamin D deficiency prevalence, including sociocultural practices and latitude. MATERIALS AND METHODS Beemster and Hattem, two Dutch 17th-19th century communities, yielded relatively high prevalences of rickets (15-24%) and residual rickets (15-24%). From the affected individuals, a subsample of 20 teeth were selected for micro-CT scanning. Thin sections were made of 17 teeth, consisting of 6 teeth with and 11 teeth without observable IGD on micro-CT that were included for method comparison. RESULTS About 19 out of 29 (65.5%) individuals (one tooth was deemed unobservable) presented with IGD on micro-CT. Eight of the 11 (72.7%) individuals without IGD on micro-CT demonstrated histologically visible IGD. In 40.7% (11/27) of the affected individuals (combined micro-CT and histology results), vitamin D deficiency was recurrent, and in four individuals, some episodes occurred at approximately annual intervals suggesting vitamin D deficiency was seasonal. In three individuals, IGD occurred in the dentine formed around birth, suggesting maternal vitamin D deficiency. DISCUSSION Micro-CT analysis of IGD is found to be a valuable non-destructive method that can improve our understanding of the influence of sociocultural practices and latitude on disease development within age and sex groups in past communities.
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Affiliation(s)
- Barbara Veselka
- Faculty of Archaeology, Human Osteoarchaeology LaboratoryLeiden UniversityLeidenThe Netherlands
| | | | - Lori D'Ortenzio
- Department of AnthropologyMcMaster UniversityHamiltonOntarioCanada
| | - Bonnie Kahlon
- Department of AnthropologyMcMaster UniversityHamiltonOntarioCanada
| | - Menno L. P. Hoogland
- Faculty of Archaeology, Human Osteoarchaeology LaboratoryLeiden UniversityLeidenThe Netherlands
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19
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Semin GR, Palma T, Acartürk C, Dziuba A. Gender is not simply a matter of black and white, or is it? Philos Trans R Soc Lond B Biol Sci 2019; 373:rstb.2017.0126. [PMID: 29914994 PMCID: PMC6015822 DOI: 10.1098/rstb.2017.0126] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2018] [Indexed: 11/12/2022] Open
Abstract
Based on research in physical anthropology, we argue that brightness marks the abstract category of gender, with light colours marking the female gender and dark colours marking the male gender. In a set of three experiments, we examine this hypothesis, first in a speeded gender classification experiment with male and female names presented in black and white. As expected, male names in black and female names in white are classified faster than the reverse gender-colour combinations. The second experiment relies on a gender classification task involving the disambiguation of very briefly appearing non-descript stimuli in the form of black and white ‘blobs’. The former are classified predominantly as male and the latter as female names. Finally, the processes driving light and dark object choices for males and females are examined by tracking the number of fixations and their duration in an eye-tracking experiment. The results reveal that when choosing for a male target, participants look longer and make more fixations on dark objects, and the same for light objects when choosing for a female target. The implications of these findings, which repeatedly reveal the same data patterns across experiments with Dutch, Portuguese and Turkish samples for the abstract category of gender, are discussed. The discussion attempts to enlarge the subject beyond mainstream models of embodied grounding. This article is part of the theme issue ‘Varieties of abstract concepts: development, use and representation in the brain’.
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Affiliation(s)
- Gün R Semin
- William James Center for Research, ISPA - Instituto Universitário, Rua Jardim do Tabaco 41, 1149-041 Lisboa, Portugal .,Department of Psychology, Utrecht University, 3584 CS Utrecht, The Netherlands
| | - Tomás Palma
- CICPSI, Faculdade de Psicologia, Universidade de Lisboa, 1649-013 Lisboa, Portugal
| | - Cengiz Acartürk
- Informatics Insitute, Department of Cognitive Sciences, Middle East Technical University, 06800 Ankara, Turkey
| | - Aleksandra Dziuba
- William James Center for Research, ISPA - Instituto Universitário, Rua Jardim do Tabaco 41, 1149-041 Lisboa, Portugal
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20
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Katsara MA, Nothnagel M. True colors: A literature review on the spatial distribution of eye and hair pigmentation. Forensic Sci Int Genet 2019; 39:109-118. [DOI: 10.1016/j.fsigen.2019.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 12/11/2018] [Accepted: 01/01/2019] [Indexed: 10/27/2022]
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21
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Pereira LA, Luz FB, Carneiro CMMDO, Xavier ALR, Kanaan S, Miot HA. Evaluation of vitamin D plasma levels after mild exposure to the sun with photoprotection. An Bras Dermatol 2019; 94:56-61. [PMID: 30726465 PMCID: PMC6360984 DOI: 10.1590/abd1806-4841.20198070] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 04/28/2018] [Indexed: 11/21/2022] Open
Abstract
BACKGROUND Most of the organism's vitamin D (VD) is obtained through the cutaneous synthesis after exposure to the sun's UVB radiation. Sunscreens are indicated for the prevention of actinic damage to the skin, however, there are few clinical trials assessing the synthesis of cutaneous VD in real-life situations of sun exposure with ordinary clothing and usual photoprotection. OBJECTIVES To evaluate the synthesis of VD with suberythemal sun exposure in healthy adults using topical photoprotection (SPF 30). METHODS Quasi-experimental study, conducted at Rio de Janeiro (Brazil), during winter, with 95 healthy adults who had 25-OH-VD checked twice, 24 hours apart, and were exposed to the sun (UVB=20 mJ/cm2), according to a randomized grouping: SC - use of SPF 30 on the face, neck and chest (n=64), NO - no sunscreens (n=10), CO - confined from sun exposure for 24h (n=21). The groups were matched according to the propensity score related to gender, age, phototype, body mass index, glycosylated hemoglobin and baseline levels of VD. The outcome evaluated was the variation (ΔVD) in serum level of 25-OH-VD (ng/ml) between the groups. RESULTS A statistically significant difference was identified between CO and SC groups [median (p25-p75)]: ΔVD =1.4 (-0.3-3.6) vs. 5.5 (4.8-6.6); p<0.01. There was no difference between SC and NO groups: 5.4 (3.1-6.1) vs. 4.1 (2.5-6.0); p=0.17. STUDY LIMITATIONS Laboratory analysis technique (chemiluminescence) with great variability, loss of food intake standardatization, unbalanced groups. CONCLUSIONS Suberythemal sun exposure with sunscreen (SPF 30) provides similar vitamin D serum variation than without photoprotection in healthy adults.
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Affiliation(s)
- Luiza Alonso Pereira
- Department of Dermatology, Universidade Federal Fluminense,
Niterói (RJ), Brasil
| | - Flávio Barbosa Luz
- Discipline of Dermatology, Department of Dermatology, Universidade
Federal Fluminense, Niterói (RJ), Brasil
| | | | - Ana Lucia Rampazzo Xavier
- Discipline of Pathology, Department of Pathology-Clinical
Biochemistry, Universidade Federal Fluminenese, Niterói (RJ), Brasil
| | - Salim Kanaan
- Discipline of Pathology, Department of Pathology-Clinical
Biochemistry, Universidade Federal Fluminenese, Niterói (RJ), Brasil
| | - Hélio Amante Miot
- Discipline of Dermatology, Department of Dermatology and
Radiotherapy, Universidade Estadual Paulista, Botucatu (SP), Brasil
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22
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Valencia-Vera E, Aguilera J, Cobos A, Bernabó JL, Pérez-Valero V, Herrera-Ceballos E. Association between seasonal serum folate levels and ultraviolet radiation. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2019; 190:66-71. [DOI: 10.1016/j.jphotobiol.2018.10.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2018] [Revised: 10/10/2018] [Accepted: 10/11/2018] [Indexed: 12/11/2022]
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23
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Iliescu FM, Chaplin G, Rai N, Jacobs GS, Basu Mallick C, Mishra A, Thangaraj K, Jablonski NG. The influences of genes, the environment, and social factors on the evolution of skin color diversity in India. Am J Hum Biol 2018; 30:e23170. [PMID: 30099804 DOI: 10.1002/ajhb.23170] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 06/18/2018] [Accepted: 07/09/2018] [Indexed: 12/21/2022] Open
Abstract
OBJECTIVES Skin color is a highly visible and variable trait across human populations. It is not yet clear how evolutionary forces interact to generate phenotypic diversity. Here, we sought to unravel through an integrative framework the role played by three factors-demography and migration, sexual selection, and natural selection-in driving skin color diversity in India. METHODS Skin reflectance data were collected from 10 diverse socio-cultural populations along the latitudinal expanse of India, including both sexes. We first looked at how skin color varies within and between these populations. Second, we compared patterns of sexual dimorphism in skin color. Third, we studied the influence of ultraviolet radiation on skin color throughout India. Finally, we attempted to disentangle the interactions between these factors in the context of available genetic data. RESULTS We found that the relative importance of these forces varied between populations. Social factors and population structure have played a stronger role than natural selection in shaping skin color diversity across India. Phenotypic overprinting resulted from additional genetic mutations overriding the skin lightening effect of variants such as the SLC24A5 rs1426654-A allele in some populations, in the context of the variable influence of sexual selection. Furthermore, specific genotypes are not associated reliably with specific skin color phenotypes. This result has relevance for DNA forensics and ancient DNA research. CONCLUSIONS India is a crucible of macro- and micro-evolutionary forces, and the complex interactions of physical and social forces are visible in the patterns of skin color seen today in the country.
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Affiliation(s)
- Florin Mircea Iliescu
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom.,Centro de Estudios Interculturales e Indígenas - CIIR, P. Universidad Católica de Chile, Santiago, Chile
| | - George Chaplin
- Department of Anthropology, The Pennsylvania State University, University Park, State Park, Pennsylvania
| | - Niraj Rai
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India.,Birbal Sahni Institute of Palaeosciences, Lucknow, India
| | - Guy S Jacobs
- Complexity Institute, Nanyang Technological University, Singapore
| | - Chandana Basu Mallick
- Estonian Biocentre, Tartu, Estonia.,The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, United Kingdom
| | - Anshuman Mishra
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, India
| | | | - Nina G Jablonski
- Department of Anthropology, The Pennsylvania State University, University Park, State Park, Pennsylvania
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Abstract
The skin is the first line of defense against the environment, with the epidermis as the outermost tissue providing much of the barrier function. Given its direct exposure to and encounters with the environment, the epidermis must evolve to provide an optimal barrier for the survival of an organism. Recent advances in genomics have identified a number of genes for the human skin barrier that have undergone evolutionary changes since humans diverged from chimpanzees. Here, we highlight a selection of key and innovative genetic findings for skin barrier evolution in our divergence from our primate ancestors and among modern human populations.
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Affiliation(s)
- Erin A. Brettmann
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for Pharmacogenomics, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA
| | - Cristina de Guzman Strong
- Division of Dermatology, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for Pharmacogenomics, Department of Medicine, Washington University School of Medicine, St. Louis, MO, USA
- Center for the Study of Itch, Washington University School of Medicine, St. Louis, MO, USA
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25
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Putilov AA, Dorokhov VB, Puchkova AN, Arsenyev GN, Sveshnikov DS. Genetic-based signatures of the latitudinal differences in chronotype. BIOL RHYTHM RES 2018. [DOI: 10.1080/09291016.2018.1465249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Arcady A. Putilov
- Research Group for Math-Modeling of Biomedical Systems, The Research Institute for Molecular Biology and Biophysics, Novosibirsk, Russia
| | - Vladimir B. Dorokhov
- Laboratory of Sleep/Wake Neurobiology, the Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, Moscow, Russia
| | - Alexandra N. Puchkova
- Laboratory of Sleep/Wake Neurobiology, the Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, Moscow, Russia
- Center for Cognition and Communication, Pushkin State Russian Language Institute, Moscow, Russia
| | - Gleb N. Arsenyev
- Laboratory of Sleep/Wake Neurobiology, the Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, Moscow, Russia
| | - Dmitry S. Sveshnikov
- Department of Normal Physiology, Medical Institute, Peoples’ Friendship University of Russia, Moscow, Russia
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26
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Delmore JL, Brennan PLR, Orr TJ. Reproductive melanization may protect sperm from harmful solar radiation. Evol Ecol 2018. [DOI: 10.1007/s10682-018-9932-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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27
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Putilov AA, Dorokhov VB, Poluektov MG. How have our clocks evolved? Adaptive and demographic history of the out-of-African dispersal told by polymorphic loci in circadian genes. Chronobiol Int 2017; 35:511-532. [DOI: 10.1080/07420528.2017.1417314] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Arcady A. Putilov
- Research Group for Math-Modeling of Biomedical Systems, the Research Institute for Molecular Biology and Biophysics, Novosibirsk, Russia
| | - Vladimir B. Dorokhov
- Laboratory of Sleep/Wake Neurobiology, The Institute of Higher Nervous Activity and Neurophysiology of the Russian Academy of Sciences, Moscow, Russia
| | - Michael G. Poluektov
- Department of Nervous Diseases, Institute of Professional Education, I.M. Sechenov 1-st Moscow State Medical University, Moscow, Russia
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Liu YH, Wang L, Xu T, Guo X, Li Y, Yin TT, Yang HC, Hu Y, Adeola AC, Sanke OJ, Otecko NO, Wang M, Ma Y, Charles OS, Sinding MHS, Gopalakrishnan S, Alfredo Samaniego J, Hansen AJ, Fernandes C, Gaubert P, Budd J, Dawuda PM, Knispel Rueness E, Jiang L, Zhai W, Gilbert MTP, Peng MS, Qi X, Wang GD, Zhang YP. Whole-Genome Sequencing of African Dogs Provides Insights into Adaptations against Tropical Parasites. Mol Biol Evol 2017; 35:287-298. [DOI: 10.1093/molbev/msx258] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
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Jablonski NG, Chaplin G. The colours of humanity: the evolution of pigmentation in the human lineage. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160349. [PMID: 28533464 PMCID: PMC5444068 DOI: 10.1098/rstb.2016.0349] [Citation(s) in RCA: 69] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/09/2016] [Indexed: 12/16/2022] Open
Abstract
Humans are a colourful species of primate, with human skin, hair and eye coloration having been influenced by a great variety of evolutionary forces throughout prehistory. Functionally naked skin has been the physical interface between the physical environment and the human body for most of the history of the genus Homo, and hence skin coloration has been under intense natural selection. From an original condition of protective, dark, eumelanin-enriched coloration in early tropical-dwelling Homo and Homo sapiens, loss of melanin pigmentation occurred under natural selection as Homo sapiens dispersed into non-tropical latitudes of Africa and Eurasia. Genes responsible for skin, hair and eye coloration appear to have been affected significantly by population bottlenecks in the course of Homo sapiens dispersals. Because specific skin colour phenotypes can be created by different combinations of skin colour-associated genetic markers, loss of genetic variability due to genetic drift appears to have had negligible effects on the highly redundant genetic 'palette' for the skin colour. This does not appear to have been the case for hair and eye coloration, however, and these traits appear to have been more strongly influenced by genetic drift and, possibly, sexual selection.This article is part of the themed issue 'Animal coloration: production, perception, function and application'.
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Affiliation(s)
- Nina G Jablonski
- Department of Anthropology, The Pennsylvania State University, 409 Carpenter Building, University Park, PA 16802, USA
| | - George Chaplin
- Department of Anthropology, The Pennsylvania State University, 409 Carpenter Building, University Park, PA 16802, USA
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Tadokoro R, Takahashi Y. Intercellular transfer of organelles during body pigmentation. Curr Opin Genet Dev 2017; 45:132-138. [PMID: 28605672 DOI: 10.1016/j.gde.2017.05.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 05/29/2017] [Accepted: 05/29/2017] [Indexed: 01/16/2023]
Abstract
The intercellular transfer of the melanin-producing organelle, called melanosome, from melanocytes to adjacent keratinocytes, is largely responsible for the coat colors and skin pigmentation of amniotes (birds, reptiles, and mammals). Although several hypotheses of melanin-transfer were proposed mainly by in vitro studies and electron microscopies, how the melanosome transfer takes place in the actual skin remained unclear. With advances in technologies of gene manipulations and high-resolution microscopy that allow direct visualization of plasma membrane, we are beginning to understand the amazing behaviors and dynamics of melanocytes. Studies in melanosome transfer further provide a clue to understand a general principle of intercellular organelle transport, including the intercellular translocations of mitochondria.
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Affiliation(s)
- Ryosuke Tadokoro
- Department of Zoology, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan
| | - Yoshiko Takahashi
- Department of Zoology, Graduate School of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Kyoto 606-8502, Japan; AMED Core Research for Evolutional Science and Technology (AMED-CREST), Japan Agency for Medical Research and Development (AMED), Chiyoda-ku, Tokyo 100-0004, Japan.
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Brickley MB, D’Ortenzio L, Kahlon B, Schattmann A, Ribot I, Raguin E, Bertrand B. Ancient Vitamin D Deficiency: Long-Term Trends. CURRENT ANTHROPOLOGY 2017. [DOI: 10.1086/691683] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Walsh S, Chaitanya L, Breslin K, Muralidharan C, Bronikowska A, Pospiech E, Koller J, Kovatsi L, Wollstein A, Branicki W, Liu F, Kayser M. Global skin colour prediction from DNA. Hum Genet 2017; 136:847-863. [PMID: 28500464 PMCID: PMC5487854 DOI: 10.1007/s00439-017-1808-5] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Accepted: 05/03/2017] [Indexed: 12/14/2022]
Abstract
Human skin colour is highly heritable and externally visible with relevance in medical, forensic, and anthropological genetics. Although eye and hair colour can already be predicted with high accuracies from small sets of carefully selected DNA markers, knowledge about the genetic predictability of skin colour is limited. Here, we investigate the skin colour predictive value of 77 single-nucleotide polymorphisms (SNPs) from 37 genetic loci previously associated with human pigmentation using 2025 individuals from 31 global populations. We identified a minimal set of 36 highly informative skin colour predictive SNPs and developed a statistical prediction model capable of skin colour prediction on a global scale. Average cross-validated prediction accuracies expressed as area under the receiver-operating characteristic curve (AUC) ± standard deviation were 0.97 ± 0.02 for Light, 0.83 ± 0.11 for Dark, and 0.96 ± 0.03 for Dark-Black. When using a 5-category, this resulted in 0.74 ± 0.05 for Very Pale, 0.72 ± 0.03 for Pale, 0.73 ± 0.03 for Intermediate, 0.87±0.1 for Dark, and 0.97 ± 0.03 for Dark-Black. A comparative analysis in 194 independent samples from 17 populations demonstrated that our model outperformed a previously proposed 10-SNP-classifier approach with AUCs rising from 0.79 to 0.82 for White, comparable at the intermediate level of 0.63 and 0.62, respectively, and a large increase from 0.64 to 0.92 for Black. Overall, this study demonstrates that the chosen DNA markers and prediction model, particularly the 5-category level; allow skin colour predictions within and between continental regions for the first time, which will serve as a valuable resource for future applications in forensic and anthropologic genetics.
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Affiliation(s)
- Susan Walsh
- Department of Biology, Indiana University Purdue University Indianapolis (IUPUI), Indianapolis, IN, USA.
| | - Lakshmi Chaitanya
- Department of Genetic Identification, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands
| | - Krystal Breslin
- Department of Biology, Indiana University Purdue University Indianapolis (IUPUI), Indianapolis, IN, USA
| | - Charanya Muralidharan
- Department of Biology, Indiana University Purdue University Indianapolis (IUPUI), Indianapolis, IN, USA
| | - Agnieszka Bronikowska
- Department of Dermatology, Collegium Medicum of the Jagiellonian University, Kraków, Poland
| | - Ewelina Pospiech
- Faculty of Biology and Earth Sciences, Institute of Zoology, Jagiellonian University, Kraków, Poland
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
| | - Julia Koller
- Department of Genetic Identification, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands
| | - Leda Kovatsi
- Laboratory of Forensic Medicine and Toxicology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Andreas Wollstein
- Section of Evolutionary Biology, Department of Biology II, University of Munich LMU, Planegg-Martinsried, Germany
| | - Wojciech Branicki
- Malopolska Centre of Biotechnology, Jagiellonian University, Kraków, Poland
- Central Forensic Laboratory of the Police, Warsaw, Poland
| | - Fan Liu
- Department of Genetic Identification, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands
- Key Laboratory of Genomic and Precision Medicine, Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Manfred Kayser
- Department of Genetic Identification, Erasmus MC University Medical Centre Rotterdam, Rotterdam, The Netherlands.
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Jarrett SG, Carter KM, D'Orazio JA. Paracrine regulation of melanocyte genomic stability: a focus on nucleotide excision repair. Pigment Cell Melanoma Res 2017; 30:284-293. [PMID: 28192636 PMCID: PMC5411317 DOI: 10.1111/pcmr.12582] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Accepted: 02/08/2017] [Indexed: 02/06/2023]
Abstract
UV radiation is a major environmental risk factor for the development of melanoma by causing DNA damage and mutations. Resistance to UV damage is largely determined by the capacity of melanocytes to respond to UV injury by repairing mutagenic photolesions. The nucleotide excision repair (NER) pathway is the major mechanism by which cells correct UV photodamage. This multistep process involves the basic steps of damage recognition, isolation, localized strand unwinding, assembly of a repair complex, excision of the damage-containing strand 3' and 5' to the photolesion, synthesis of a sequence-appropriate replacement strand, and finally ligation to restore continuity of genomic DNA. In melanocytes, the efficiency of NER is regulated by several hormonal pathways including the melanocortin and endothelin signaling pathways. Elucidating molecular mechanisms by which melanocyte DNA repair is regulated offers the possibility of developing novel melanoma-preventive strategies to reduce UV mutagenesis, especially in UV-sensitive melanoma-prone individuals.
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Affiliation(s)
- Stuart Gordon Jarrett
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA
- Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, KY, USA
| | | | - John August D'Orazio
- Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, USA
- Department of Toxicology and Cancer Biology, University of Kentucky College of Medicine, Lexington, KY, USA
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY, USA
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, USA
- Department of Pediatrics, University of Kentucky College of Medicine, Lexington, KY, USA
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Melanosome transfer to keratinocyte in the chicken embryonic skin is mediated by vesicle release associated with Rho-regulated membrane blebbing. Sci Rep 2016; 6:38277. [PMID: 27910904 PMCID: PMC5133614 DOI: 10.1038/srep38277] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Accepted: 11/07/2016] [Indexed: 02/08/2023] Open
Abstract
During skin pigmentation in amniotes, melanin synthesized in the melanocyte is transferred to keratinocytes by a particle called the melanosome. Previous studies, mostly using dissociated cultured cells, have proposed several different models that explain how the melanosome transfer is achieved. Here, using a technique that labels the plasma membrane of melanocytes within a three-dimensional system that mimics natural tissues, we have visualized the plasma membrane of melanocytes with EGFP in chicken embryonic skin. Confocal time-lapse microscopy reveals that the melanosome transfer is mediated, at least in part, by vesicles produced by plasma membrane. Unexpectedly, the vesicle release is accompanied by the membrane blebbing of melanocytes. Blebs that have encapsulated a melanosome are pinched off to become vesicles, and these melanosome-containing vesicles are finally engulfed by neighboring keratinocytes. For both the membrane blebbing and vesicle release, Rho small GTPase is essential. We further show that the membrane vesicle-mediated melanosome transfer plays a significant role in the skin pigmentation. Given that the skin pigmentation in inter-feather spaces in chickens is similar to that in inter-hair spaces of humans, our findings should have important consequences in cosmetic medicine.
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de Vries E, Sierra M, Piñeros M, Loria D, Forman D. The burden of cutaneous melanoma and status of preventive measures in Central and South America. Cancer Epidemiol 2016; 44 Suppl 1:S100-S109. [PMID: 27034057 DOI: 10.1016/j.canep.2016.02.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2015] [Revised: 01/29/2016] [Accepted: 02/09/2016] [Indexed: 11/23/2022]
Abstract
RATIONALE AND OBJECTIVE Very little is known about the burden of cutaneous melanoma in Central and South America, despite the existence of a reasonable amount of population-based data. We present data on melanoma incidence calculated in a standardized way for Central and South America, as well as an overview of primary and secondary prevention issues in the region. METHODS Cancer registry data on all incident cases reported in the different registries present in Central and South America were combined to provide registry-based country estimates of age-standardized, sex-specific cutaneous melanoma incidence overall, and by histological subtype and anatomical site. A literature search provided additional information. RESULTS Age-standardized incidence rates were between 1 and 5 per 100,000 and tended to be higher further away from the equator. Cutaneous melanomas of the acral type, mostly occurring on the lower limbs, are a distinguishing feature of melanoma in Central and South America in comparison with high-incidence areas. Several preventive measures, both primary and secondary, are in place, albeit largely without evaluation. CONCLUSION Due to incomplete registration and different registration practices, reliable and comparable data on melanoma were difficult to obtain; thus it is likely that the true burden of melanoma in Central and South America has been underestimated. The different characteristics of the cutaneous melanoma patient population in terms of anatomical site and histological type distribution imply a need for adapted primary and secondary prevention measures. The generally high ambient ultraviolet radiation levels require sufficient sun protection measures.
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Affiliation(s)
- Esther de Vries
- International Agency for Research on Cancer, Section of Cancer Surveillance, Lyon, France; National Cancer Institute, Directorate of Research, Surveillance, Prevention and Promotion, Colombia; Erasmus MC University Medical Center, Department of Public Health, Rotterdam, The Netherlands.
| | - Mónica Sierra
- International Agency for Research on Cancer, Section of Cancer Surveillance, Lyon, France
| | - Marion Piñeros
- International Agency for Research on Cancer, Section of Cancer Surveillance, Lyon, France
| | - Dora Loria
- Argentinian Registry of Cutaneous Melanoma, Argentina
| | - David Forman
- International Agency for Research on Cancer, Section of Cancer Surveillance, Lyon, France
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Fajuyigbe D, Young AR. The impact of skin colour on human photobiological responses. Pigment Cell Melanoma Res 2016; 29:607-618. [PMID: 27454804 PMCID: PMC5132026 DOI: 10.1111/pcmr.12511] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 07/11/2016] [Indexed: 01/30/2023]
Abstract
Terrestrial solar ultraviolet radiation (UVR) exerts both beneficial and adverse effects on human skin. Epidemiological studies show a lower incidence of skin cancer in people with pigmented skins compared to fair skins. This is attributed to photoprotection by epidermal melanin, as is the poorer vitamin D status of those with darker skins. We summarize a wide range of photobiological responses across different skin colours including DNA damage and immunosuppression. Some studies show the generally modest photoprotective properties of melanin, but others show little or no effect. DNA photodamage initiates non‐melanoma skin cancer and is reduced by a factor of about 3 in pigmented skin compared with white skin. This suggests that if such a modest reduction in DNA damage can result in the significantly lower skin cancer incidence in black skin, the use of sunscreen protection might be extremely beneficial for susceptible population. Many contradictory results may be explained by protocol differences, including differences in UVR spectra and exposure protocols. We recommend that skin type comparisons be done with solar‐simulated radiation and standard erythema doses or physical doses (J/m2) rather than those based solely on clinical endpoints such as minimal erythema dose (MED).
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Affiliation(s)
- Damilola Fajuyigbe
- Division of Genetics and Molecular Medicine, Faculty of Life Sciences and Medicine, St John's Institute of Dermatology, King's College London, London, UK
| | - Antony R Young
- Division of Genetics and Molecular Medicine, Faculty of Life Sciences and Medicine, St John's Institute of Dermatology, King's College London, London, UK
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Elias PM, Williams ML. Basis for the gain and subsequent dilution of epidermal pigmentation during human evolution: The barrier and metabolic conservation hypotheses revisited. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 2016; 161:189-207. [PMID: 27324932 DOI: 10.1002/ajpa.23030] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 05/27/2016] [Accepted: 05/29/2016] [Indexed: 12/25/2022]
Abstract
The evolution of human skin pigmentation must address both the initial evolution of intense epidermal pigmentation in hominins, and its subsequent dilution in modern humans. While many authorities believe that epidermal pigmentation evolved to protect against either ultraviolet B (UV-B) irradiation-induced mutagenesis or folic acid photolysis, we hypothesize that pigmentation augmented the epidermal barriers by shifting the UV-B dose-response curve from toxic to beneficial. Whereas erythemogenic UV-B doses produce apoptosis and cell death, suberythemogenic doses benefit permeability and antimicrobial function. Heavily melanized melanocytes acidify the outer epidermis and emit paracrine signals that augment barrier competence. Modern humans, residing in the cooler, wetter climes of south-central Europe and Asia, initially retained substantial pigmentation. While their outdoor lifestyles still permitted sufficient cutaneous vitamin D3 (VD3) synthesis, their marginal nutritional status, coupled with cold-induced caloric needs, selected for moderate pigment reductions that diverted limited nutritional resources towards more urgent priorities (=metabolic conservation). The further pigment-dilution that evolved as humans reached north-central Europe (i.e., northern France, Germany), likely facilitated cutaneous VD3 synthesis, while also supporting ongoing, nutritional requirements. But at still higher European latitudes where little UV-B breaches the atmosphere (i.e., present-day UK, Scandinavia, Baltic States), pigment dilution alone could not suffice. There, other nonpigment-related mutations evolved to facilitate VD3 production; for example, in the epidermal protein, filaggrin, resulting in reduced levels of its distal metabolite, trans-urocanic acid, a potent UV-B chromophore. Thus, changes in human pigmentation reflect a complex interplay between latitude, climate, diet, lifestyle, and shifting metabolic priorities.
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Affiliation(s)
- Peter M Elias
- Department of Veterans Affairs Medical Center, Dermatology Service, University of California San Francisco, California. .,Department of Dermatology, Dermatology Service, University of California San Francisco, California.
| | - Mary L Williams
- Department of Dermatology, University of California, San Francisco, California.,Department of Pediatrics, University of California, San Francisco, California
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Abstract
The well-documented latitudinal clines of genes affecting human skin color presumably arise from the need for protection from intense ultraviolet radiation (UVR) vs. the need to use UVR for vitamin D synthesis. Sampling 751 subjects from a broad range of latitudes and skin colors, we investigated possible multilocus correlated adaptation of skin color genes with the vitamin D receptor gene (VDR), using a vector correlation metric and network method called BlocBuster. We discovered two multilocus networks involving VDR promoter and skin color genes that display strong latitudinal clines as multilocus networks, even though many of their single gene components do not. Considered one by one, the VDR components of these networks show diverse patterns: no cline, a weak declining latitudinal cline outside of Africa, and a strong in- vs. out-of-Africa frequency pattern. We confirmed these results with independent data from HapMap. Standard linkage disequilibrium analyses did not detect these networks. We applied BlocBuster across the entire genome, showing that our networks are significant outliers for interchromosomal disequilibrium that overlap with environmental variation relevant to the genes’ functions. These results suggest that these multilocus correlations most likely arose from a combination of parallel selective responses to a common environmental variable and coadaptation, given the known Mendelian epistasis among VDR and the skin color genes.
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Abstract
Humans are unique in many respects including being furless, striding bipeds that excel at walking and running long distances in hot conditions. This review summarizes what we do and do not know about the evolution of these characteristics, and how they are related. Although many details remain poorly known, the first hominins (species more closely related to humans than to chimpanzees) apparently diverged from the chimpanzee lineage because of selection for bipedal walking, probably because it improved their ability to forage efficiently. However, because bipedal hominins are necessarily slow runners, early hominins in open habitats likely benefited from improved abilities to dump heat in order to forage safely during times of peak heat when predators were unable to hunt them. Endurance running capabilities evolved later, probably as adaptations for scavenging and then hunting. If so, then there would have been strong selection for heat-loss mechanisms, especially sweating, to persistence hunt, in which hunters combine endurance running and tracking to drive their prey into hyperthermia. As modern humans dispersed into a wide range of habitats over the last few hundred thousand years, recent selection has helped populations cope better with a broader range of locomotor and thermoregulatory challenges, but all humans remain essentially adapted for long distance locomotion rather than speed, and to dump rather than retain heat.
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Affiliation(s)
- Daniel E Lieberman
- Department of Human Evolutionary Biology, Harvard University, 11 Divinity Avenue, Cambridge, MA 02138, USA
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Maresca V, Flori E, Picardo M. Skin phototype: a new perspective. Pigment Cell Melanoma Res 2015; 28:378-89. [DOI: 10.1111/pcmr.12365] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 03/16/2015] [Indexed: 12/21/2022]
Affiliation(s)
- Vittoria Maresca
- Laboratory of Cutaneous Physiopathology and Integrated Centre of Metabolomics Research; San Gallicano Dermatologic Institute; Rome Italy
| | - Enrica Flori
- Laboratory of Cutaneous Physiopathology and Integrated Centre of Metabolomics Research; San Gallicano Dermatologic Institute; Rome Italy
| | - Mauro Picardo
- Laboratory of Cutaneous Physiopathology and Integrated Centre of Metabolomics Research; San Gallicano Dermatologic Institute; Rome Italy
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Saint-Léger D. The colour of the human skin: fruitful science, unsuitable wordings. Int J Cosmet Sci 2015; 37:259-65. [PMID: 25533569 DOI: 10.1111/ics.12194] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 12/12/2014] [Indexed: 12/13/2022]
Abstract
A review of the various facets of the colour of human skin is proposed. It aims first at illustrating the paradoxical association of the remarkable recent scientific advances that characterize changes in the skin colour, with some totally inappropriate or outdated phrasings used in its communication. As a second objective, it aims at proposing an alternative to these wordings. The latter would combine six shade types, defined by Individual Type Angle (ITA) values, a coloured reference chart and associated colour adjectives, highly corresponding to the six Phototypes previously defined by Fitzpatrick. Such alternative would overcome most references to both ethnic- and ethical-related issues.
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Voegeli R, Rawlings AV, Summers B. Facial skin pigmentation is not related to stratum corneum cohesion, basal transepidermal water loss, barrier integrity and barrier repair. Int J Cosmet Sci 2015; 37:241-52. [PMID: 25482263 DOI: 10.1111/ics.12189] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2014] [Accepted: 11/26/2014] [Indexed: 12/11/2022]
Abstract
OBJECTIVE Hypotheses have been developed for the evolutionary selection of skin pigmentation one of which relates to improved skin barrier function. The aim of this study was to compare facial skin condition on photoexposed (cheek) and photoprotected (post-auricular) sites of naturally pigmented subjects of different ethnicities (Fitzpatrick skin phototypes II/III and V/VI) and Albino African subjects to understand better the relationship between facial stratum corneum (SC) barrier function, skin surface pH and skin pigmentation. METHODS Expert grading of skin conditions, capacitance, skin surface pH and skin barrier function measurements were performed. For the latter, transepidermal water loss (TEWL) measurements before (basal TEWL), after 3, 6 and 9 consecutive tape strippings (SC integrity) and 3.5 and 24 h post tape stripping (barrier recovery) were taken. Amounts of SC protein removed during stripping were estimated using infrared densitometry (SC cohesion). RESULTS Firstly, correlation analysis of the biometric data of the Black African and Caucasian subjects showed there to be no relationship between skin surface pH and ITA° values nor pH and ITA° with basal TEWL. Neither skin surface pH nor ITA° correlated with SC integrity and barrier recovery measurements, but skin surface pH correlated with SC cohesion. ITA° values were correlated with skin hydration. Secondly, on comparing the three ethnic groups, severe skin photodamage was observed in the Albino African subjects and their SC was thicker. Whereas their basal TEWL was elevated, superior values for SC integrity and barrier recovery were measured. No differences in basal TEWL, SC integrity and barrier recovery were found between the other two subject groups. Equally, SC cohesion and skin surface pH values were similar among the three groups. CONCLUSION There was no relationship between ITA° values and basal TEWL, SC integrity, SC cohesion and barrier recovery, but ITA° was correlated with skin hydration. Skin surface pH, irrespective of ITA° values, correlated with SC cohesion, indicating a greater intracorneal cohesion at lower pH values. Thus, pigmentation has no effect on SC barrier properties but was related to skin hydration. On comparing the three ethnic groups, Albino African SC was found to be superior to the Caucasian and Black African subjects in terms of SC integrity and barrier recovery but not basal TEWL. The Albino African subjects also have a thicker SC which contributes to their better SC integrity. No differences in skin barrier functionality or skin surface pH were observed for the other two groups. Skin hydration was, however, greatest in the Black African subjects. Our data support the evolutionary hypothesis that pigmentation protects the skin from UV irradiation and thereby the skin barrier but not the skin pigmentation-/pH-driven adaptive skin barrier hypothesis.
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Affiliation(s)
- R Voegeli
- DSM Nutritional Products Ltd., PO Box 2676, Bldg. 203.4/86, 4002, Basel, Switzerland
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Liu-Smith F, Poe C, Farmer PJ, Meyskens FL. Amyloids, melanins and oxidative stress in melanomagenesis. Exp Dermatol 2014; 24:171-4. [PMID: 25271672 DOI: 10.1111/exd.12559] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2014] [Indexed: 12/26/2022]
Abstract
Melanoma has traditionally been viewed as an ultraviolet (UV) radiation-induced malignancy. While UV is a common inducing factor, other endogenous stresses such as metal ion accumulation or the melanin pigment itself may provide alternative pathways to melanoma progression. Eumelanosomes within melanoma often exhibit disrupted membranes and fragmented pigment which may be due to alterations in their amyloid-based striated matrix. The melanosomal amyloid can itself be toxic, especially in combination with reactive oxygen species (ROS) and reactive nitrogen species (RNS) generated by endogenous NADPH oxidase (NOX) and nitric oxide synthase (NOS) enzymes, a toxic mix that may initiate melanomagenesis. Further understanding of the loss of the melanosomal organization, the behaviour of the exposed melanin and the induction of ROS/RNS in melanomas may provide critical insights into this deadly disease.
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Affiliation(s)
- Feng Liu-Smith
- Department of Epidemiology, University of California School of Medicine, Irvine, CA, USA; Department of Medicine, University of California School of Medicine, Irvine, CA, USA; Chao Family Comprehensive Cancer Center, University of California School of Medicine, Irvine, CA, USA
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