race and skin color variation case study answer key

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• Human Skin Color Variation

The DNA of all people around the world contains a record of how living populations are related to one another, and how far back those genetic relationships go. Understanding the spread of modern human populations relies on the identification of genetic markers, which are rare mutations to DNA that are passed on through generations. Different populations carry distinct markers. Once markers have been identified, they can be traced back in time to their origin – the most recent common ancestor of everyone who carries the marker. Following these markers through the generations reveals a genetic tree of many diverse branches, each of which may be followed back to where they all join – a common African root.

The mitochondria inside each cell are the power stations of the body; they generate the energy necessary for cellular organisms to live and function. Mitochondria have their own DNA, abbreviated mtDNA, distinct from the DNA inside the nucleus of each cell.  mtDNA is the female equivalent of a surname: it passes down from mother to offspring in every generation, and the more female offspring a mother and her female descendants produce, the more common her mtDNA type will become. But surnames mutate across many generations, and so mtDNA types have changed over the millennia. A natural mutation modifying the mtDNA in the reproductive cells of one woman will from then on characterize her descendants. These two fundamentals – inheritance along the mother line and occasional mutation – allow geneticists to reconstruct ancient genetic prehistory from the variations in mtDNA types that occur today around the world.

Population genetics often use haplogroups, which are branches on the tree of early human migrations and genetic evolution. They are defined by genetic mutations or "markers" found in molecular testing of chromosomes and mtDNA. These markers link the members of a haplogroup back to the marker's first appearance in the group's most recent common ancestor. Haplogroups often have a geographic relation.

A synthesis of mtDNA studies concluded that an early exodus out of Africa, evidenced by the remains at Skhul and Qafzeh by 135,000 to 100,000 years ago, has not left any descendants in today’s Eurasian mtDNA pool. By contrast, the successful exodus of women carrying M and N mtDNA, ancestral to all non-African mtDNA today, at around 60,000 years ago may coincide with the unprecedented low sea-levels at that time, probably opening a route across the Red Sea to Yemen. Another study of a subset of the human mtDNA sequence yielded similar results, finding that the most recent common ancestor of all the Eurasian, American, Australian, Papua New Guinean, and African lineages dates to between 73,000 and 57,000 years ago, while the average age of convergence, or coalescence time, of the three basic non-African founding haplogroups M, N, and R is 45,000 years ago.

This information has enabled scientists to develop intriguing hypotheses about when dispersals took place to different regions of the world. These hypotheses can be tested with further studies of genetics and fossils.

Modern Human Diversity - Skin Color

Why do people from different parts of the world have different colored skin? Why do people from the tropics generally have darker skin color than those who live in colder climates? Variations in human skin color are adaptive traits that correlate closely with geography and the sun’s ultraviolet (UV) radiation.

As early humans moved into hot, open environments in search of food and water, one big challenge was keeping cool. The adaptation that was favored involved an increase in the number of sweat glands on the skin while at the same time reducing the amount of body hair. With less hair, perspiration could evaporate more easily and cool the body more efficiently. But this less-hairy skin was a problem because it was exposed to a very strong sun, especially in lands near the equator. Since strong sun exposure damages the body, the solution was to evolve skin that was permanently dark so as to protect against the sun’s more damaging rays.

Melanin, the skin's brown pigment, is a natural sunscreen that protects tropical peoples from the many harmful effects of ultraviolet (UV) rays. UV rays can, for example, strip away folic acid, a nutrient essential to the development of healthy fetuses. Yet when a certain amount of UV rays penetrates the skin, it helps the human body use vitamin D to absorb the calcium necessary for strong bones. This delicate balancing act explains why the peoples that migrated to colder geographic zones with less sunlight developed lighter skin color. As people moved to areas farther from the equator with lower UV levels, natural selection favored lighter skin which allowed UV rays to penetrate and produce essential vitamin D. The darker skin of peoples who lived closer to the equator was important in preventing folate deficiency. Measures of skin reflectance, a way to quantify skin color by measuring the amount of light it reflects, in people around the world support this idea. While UV rays can cause skin cancer, because skin cancer usually affects people after they have had children, it likely had little effect on the evolution of skin color because evolution favors changes that improve reproductive success.

There is also a third factor which affects skin color: coastal peoples who eat diets rich in seafood enjoy this alternate source of vitamin D. That means that some Arctic peoples, such as native peoples of Alaska and Canada, can afford to remain dark-skinned even in low UV areas. In the summer they get high levels of UV rays reflected from the surface of snow and ice, and their dark skin protects them from this reflected light.

Modern Human Diversity - Genetics

People today look remarkably diverse on the outside. But how much of this diversity is genetically encoded? How deep are these differences between human groups? First, compared with many other mammalian species, humans are genetically far less diverse – a counterintuitive finding, given our large population and worldwide distribution. For example, the subspecies of the chimpanzee that lives just in central Africa, Pan troglodytes troglodytes , has higher levels of diversity than do humans globally, and the genetic differentiation between the western ( P. t. verus ) and central ( P. t. troglodytes ) subspecies of chimpanzees is much greater than that between human populations.

Early studies of human diversity showed that most genetic diversity was found between individuals rather than between populations or continents and that variation in human diversity is best described by geographic gradients, or clines. A wide-ranging study published in 2004 found that 87.6% percent of the total modern human genetic diversity is accounted for by the differences between individuals, and only 9.2% between continents. In general, 5%–15% of genetic variation occurs between large groups living on different continents, with the remaining majority of the variation occurring within such groups (Lewontin 1972; Jorde et al. 2000a; Hinds et al. 2005). These results show that when individuals are sampled from around the globe, the pattern seen is not a matter of discrete clusters – but rather gradients in genetic variation (gradual geographic variations in allele frequencies) that extend over the entire world. Therefore, there is no reason to assume that major genetic discontinuities exist between peoples on different continents or "races." The authors of the 2004 study say that they ‘see no reason to assume that "races" represent any units of relevance for understanding human genetic history. An exception may be genes where different selection regimes have acted in different geographical regions. However, even in those cases, the genetic discontinuities seen are generally not "racial" or continental in nature but depend on historical and cultural factors that are more local in nature’ (Serre and Pääbo 2004: 1683-1684).

Bibliography

Cann, R., Stoneking, M., Wilson, A., 1987. Mitochondrial DNA and human evolution. Nature 352, 31-36.

Cavalli-Sforza, L.L., Menozzi, P., Piazza, A., 1994. The History and Geography of Human Genes . Princeton University Press, Princeton, NJ.

Ebersberger, I., Metzler, D., Schwarz, C., Pääbo, S., 2002. Genomewide comparison of DNA sequences between humans and chimpanzees. American Journal of Human Genetics 70, 1490–1497.

Fischer, A., Wiebe, V., Pääbo, S., Przeworski, M., 2004. Evidence for a complex demographic history of chimpanzees. Molecular Biology and Evolution 21, 799-808.

Forster, P., 2004. Ice Ages and the mitochondrial DNA chronology of human dispersals: a review. Philosophical Transactions of the Royal Society of London B 359, 255–264.

Gonder, M.K., Mortensen, H.M., Reed, F.A., de Sousa, A., Tishkoff, S.A., 2007. Whole-mtDNA genome sequence analysis of ancient African lineages. Molecular Biology and Evolution 24, 757–768.

Hinds D.A., Stuve L.L., Nilsen G.B., Halperin E., Eskin E., Ballinger D.G., Frazer K.A., Cox D.R., 2005. Whole-genome patterns of common DNA variation in three human populations.  Science  307, 1072–1079.

Ingman, M., Kaessmann, H., Pääbo, S., Gyllensten, U., 2000. Mitochondrial genome variation and the origin of modern humans. Nature 408, 708–713.

Ingman, M., Gyllensten, U., 2001. Analysis of the complete human mtDNA genome: methodology and inferences for human evolution. Journal of Heredity 2001:92, 454-461.

Jorde, L.B., Watkins, W.S., Bamshad, M.J., Dixon, M.E., Ricker, C.E., Seielstad, M.T., Batzer, M.A., 2000. The distribution of human genetic diversity: a comparison of mitochondrial, autosomal, and Y-chromosome data. American Journal of Human Genetics 66, 979–988.

Kaessmann, H., Heissig, F., von Haeseler, A., Pääbo, S., 1999. DNA sequence variation in a non-coding region of low recombination on the human X chromosome. Nature Genetics 22, 78-81.

Kaessmann, H., Wiebe, V., Weiss, G., Pääbo, S., 2001. Great ape DNA sequences reveal a reduced diversity and an expansion in humans. Nature Genetics 27, 155–156.

Kivisild, T., Shen, P., Wall, D.P., Do, B., Sung, R., Davis, K., Passarino, G., Underhill, P.A., Scharfe, C., Torroni, A., Scozzari, R., Modiano, D., Coppa, A., de Knijff, P., Feldman, M., Cavalli-Sforza, L.L., Oefner, P.J., 2006. The role of selection in the evolution of human mitochondrial genomes. Genetics 172, 373-387.

Lewontin, R., 1972. The apportionment of human diversity. Evolutionary Biology 6: 381-398.

Melnick, D.J., Hoelzer, G.A., 1993. What is mtDNA good for in the study of primate evolution? Evolutionary Anthropology 2, 2-10.

Serre, D., Pääbo, S., 2004. Evidence for gradients of human genetic diversity within and among continents. Genome Research 14, 1679-1685.

Tishkoff, S., Deitzsch, E., Speed, W., Pakstis, A., Kidd, J., Cheung, K., Bonne-Tamir, M., Santachiara-Benerecetti, A., Moral, P., Krings, M., Paabo, S., Watson, E., Reisch, N., Jenkins, T., Kidd, K., 1996. Global patterns of linkage disequilibrium at the CD4 locus and modern human origins. Science 271, 1380-1387.

Tishkoff, S.A., Reed, F.A., Friedlaender, F.R., Ehret, C., Ranciaro, A., Froment, A., Hirbo, J.B., Awomoyi, A.A., Bodo, J-M., Doumbo, O., Ibrahim, M., Juma, A.T., Kotze, M.J., Lema, G., Moore, J.H., Mortensen, H., Nyambo, T.B., Omar, S.A., Powell, K., Pretorius, G.S., Smith, M.W., Thera, M.A., Wambebe, C., Weber, J.L., and Williams, S.M. 2009. The genetic structure and history of Africans and African Americans. Science 324, 1035-1044.

Underhill, P.A., Shen, P., Lin, A.A., Jin, L., Passarino, G., Yang, W.H., Kauffman, E., Bonné-Tamir, B., Bertranpetit, J., Francalacci, P., Ibrahim, M., Jenkins, T., Kidd, J.R., Mehdi, S.Q., Seielstad, M.T., Wells, R.S., Piazza, A., Davis, R.W., Feldman, M.W., Cavalli-Sforza, L.L., Oefner, P.J., 2000. Y chromosome sequence variation and the history of human populations. Nature Genetics  26, 358-361.

Whitfield, L., Sulston, J., Goodfellow, P., 1995. A recent common ancestry for human Y chromosomes. Nature 378, 379-380.

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A molecular look at the mechanisms behind pigmentation variation

A new collaborative study offers a better understanding of genes and variants responsible for skin color, providing insights into human evolution and local adaptation..

Researchers from the University of Pennsylvania have discovered key insights into the molecular basis of skin color variations among African populations. Their findings, published in Nature Genetics , broaden the understanding of human evolution and the genetics underpinning contemporary human skin color diversity.

“Despite the abundant genetic diversity within African populations, they have been historically underrepresented in genetic studies,” says senior author Sarah Tishkoff , a Penn Integrates Knowledge University Professor with appointments in the Perelman School of Medicine and School of Arts & Sciences . “Our findings offer novel information about the genetic basis and evolutionary history of skin color diversity, contributing to a clearer depiction of human evolution.”

The story of human evolution is as rich and diverse as the adaptations found across the world’s populations, Tishkoff says. She notes that, among many adaptive traits, skin color stands out as one of the most well-known. Darker skin tones, prevalent in equatorial regions, serve as nature’s very own sunblock, evolving over millennia to shield these populations from the sun’s intense ultraviolet radiation. Conversely, lighter pigmentation, as seen in populations closer to the poles, is an adaptation to mitigate the risks of insufficient sun exposure by maximizing vitamin D production, which is triggered by UV exposure.

“Our approach involved genome-wide association studies of skin color from more than 1,500 eastern and southern African individuals as well as scanning the genome to identify genetic variants that are highly differentiated between the lightly-pigmented Khoesan-speaking San population and other darkly pigmented Africans and may play a role in local adaptation in that population,” says Yuanqing Feng, first author of the paper and a postdoctoral researcher in the Tishkoff Lab .

The researchers note that pigmentation is a complex trait influenced by hundreds of variants scattered across the genome, with the majority situated in noncoding regions. These noncoding variants may affect the expression of genes located up to one million bases away. The vast number of mutations associated with skin color and the uncertainty surrounding the target genes regulated by these mutations make it particularly arduous for researchers to find the precise genetic mechanisms governing this trait.

Feng and collaborators used massively parallel reporter assays to discern the regulatory activities of thousands of variants. This high-throughput technique narrowed down the thousands of candidates to 165 functional variants. To identify the target genes of these functional variants, Feng further constructed high-resolution chromatin interaction maps in melanocytic cells using chromatin conformation capture assays. “This is a high-resolution 3D genome map in melanoma cells that will be valuable for gene regulation studies in pigmentation and melanoma biology,” Feng says.

Using CRISPR/Cas9-based genome editing, the researchers discovered that mutations in an enhancer of OCA2, a gene associated with albinism, could lead to a 75% reduction in melanin levels when compared to control cells. Within the same OCA2 enhancer, the researchers identified two closely located regulatory variants, estimated to be 1.2 million years old and 57 thousand years old, with the latter coinciding with the period of human migration from Africa.

“This case illustrates the continuous evolution of human skin color, and it’s remarkable to observe the significant effects on skin pigmentation attributed to a single enhancer,” Feng says.

San people have relatively lighter pigmentation compared to other African populations and possess the oldest genetic lineages in humans. While it is hypothesized that the light skin color of the San may result from adaptation to a southern African environment, the genetic underpinnings of this adaptation remain elusive. The researchers pinpointed several crucial regulatory variants near MITF , LEF1, and TRPS1 that contribute to the skin color adaptation observed in the San.

“MITF , LEF1, and TRPS1 are involved in signaling pathways regulating both melanocyte differentiation and hair development,” Tishkoff says. “This suggests that the variants influencing the lighter skin pigmentation observed in the San people may also contribute to their distinctive hair morphology.” Notably, the variant near TRPS1 associated with lighter skin color is at nearly 100% frequency in the San and in most non-Africans, whereas the variant associated with darker skin color is common in most other African populations and in the darkly pigmented Melanesian population, a striking example of global adaptations to UV exposure.”

Additionally, the researchers found a novel gene impacting human skin pigmentation, CYB561A3, which regulates iron homeostasis and influences melanin levels in melanocytic cells. “To our knowledge, the role of CYB561A3 in skin pigmentation has not been reported before. Intriguingly, there have been reports linking intravenous iron infusion to skin hyperpigmentation. Given that CYB561A3 encodes an iron reductase, I am curious about the role of this protein in this process,” Tishkoff says.

“Our findings underscore the complexity of genetic factors influencing skin color and the benefits of including ethnically diverse and underrepresented populations in genetic studies,” she says. “Conducting functional studies on the impact of noncoding variants will enhance our comprehension of the genetics underlying complex human traits and disease risk.”

“The populations included in this study are from remote regions of Africa and required the use of a mobile lab set up in the field sites,” Tishkoff says. “The collaboration with our partners in Africa was key to the success of this research project.”

In future research, the Tishkoff lab would like to use its innovative functional genomics approach to identify more genetic variants contributing to human pigmentation and other adaptive traits in a larger sample of ethnically diverse Africans.

Sarah Tishkoff is the David and Lyn Silfen University Professor in Genetics and Biology and a Penn Integrates Knowledge University Professor with appointments in the Perelman School of Medicine’s Department of Genetics and Department of Medicine and in the School of Arts & Sciences’ Department of Biology at the University of Pennsylvania.

Yuanqing Feng is a postdoctoral fellow in the Tishkoff lab at Penn.

Other authors include Ning Xie, Chao Zhang, Fang Zhang, and Matthew E.B. Hansen of Penn; Fumitaka Inoue of Kyoto University; Shaohua Fan of Fudan University; Thomas Nyambo of Hubert Kairuki Memorial University; Sununguko Wata Mpoloka and Gaonyadiwe George Mokone of the University of Botswana; Charles Fokunang and Alfred K. Njamnshi of the University of Yaoundé; Gurja Belay of Addis Ababa University; Michael S. Marks of the Children’s Hospital of Philadelphia Research Institute; Elena Oancea of Brown University; and Nadav Ahituv of the University of California, San Francisco.

This research was supported by the National Institutes of Health (grants R35GM134957-01, 3UM1HG009408-02S1, 1R01GM113657-01, 5R01AR076241-02, and 1S10OD010786-01) and the Penn Skin Biology and Disease Resource-based Center (Grant NIH P30-AR069589).

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The Evolution of Human Skin Color

By Annie Prud’homme-Genereux

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While the concept of evolution by natural selection is very simple, it is often misunderstood by students. This is partly due to preconceptions they have as well as a lack of understanding or emphasis on the idea that reproductive success (and not survival) is what matters to evolution. One way to ensure that students grasp this concept is to confront them with situations that require them to examine each factor’s effect on survival and reproduction. In this case study, the evolution of human skin color is used as a means of exploring the process of evolution by natural selection. Through the progressive disclosure of data, students learn about the factors that may have exerted pressure on the evolution of this trait. Students evaluate hypotheses, predict their outcomes, evaluate them in light of new information, and reformulate them to take unexplained data into consideration. The case has been used in a first-year introductory biology course for non-majors.

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• Formulate testable hypotheses given preliminary data.
• Predict patterns that would confirm their hypothesis.
• Interpret data and compare to predicted outcomes.
• Reformulate hypotheses when in conflict with existing data.
• Identify factors that can exert evolutionary pressures (discriminate between factors that affect reproduction and those that affect survival).
• Apply the concepts of natural selection to a real situation.
• Evaluate whether sexual selection is affecting a human trait.
• Propose public policies and practices based on assimilated information.

Skin pigmentation; skin color; natural selection; evolution; vitamin D; vitamin B folate; ultraviolet light; UV light

Subject Headings

EDUCATIONAL LEVEL

High school, Undergraduate lower division

TOPICAL AREAS

Scientific method, Policy issues

TYPE/METHODS

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More than skin deep: A molecular look at the mechanisms behind pigmentation variation

A new collaborative study offers a better understanding of genes and variants responsible for skin color, providing insights into human evolution and local adaptation..

Researchers from the University of Pennsylvania have discovered key insights into the molecular basis of skin color variations among African populations. Their findings, published in Nature Genetics , broaden the understanding of human evolution and the genetics underpinning contemporary human skin color diversity.

"Despite the abundant genetic diversity within African populations, they have been historically underrepresented in genetic studies," says senior author Sarah Tishkoff, a Penn Integrates Knowledge University Professor with appointments in the Perelman School of Medicine and School of Arts & Sciences. "Our findings offer novel information about the genetic basis and evolutionary history of skin color diversity, contributing to a clearer depiction of human evolution."

The story of human evolution is as rich and diverse as the adaptations found across the world's populations, Tishkoff says. She notes that, among many adaptive traits, skin color stands out as one of the most well-known. Darker skin tones, prevalent in equatorial regions, serve as nature's very own sunblock, evolving over millennia to shield these populations from the sun's intense ultraviolet radiation. Conversely, lighter pigmentation, as seen in populations closer to the poles, is an adaptation to mitigate the risks of insufficient sun exposure by maximizing vitamin D production, which is triggered by UV exposure.

"Our approach involved genome-wide association studies of skin color from more than 1,500 eastern and southern African individuals as well as scanning the genome to identify genetic variants that are highly differentiated between lightly-pigmented Khoesan-speaking San population and other darkly pigmented Africans and may play a role in local adaptation in that population," says Yuanqing Feng, first author of the paper and a postdoctoral researcher in the Tishkoff Lab.

The researchers note that pigmentation is a complex trait influenced by hundreds of variants scattered across the genome, with the majority situated in noncoding regions. These noncoding variants may affect the expression of genes located up to one million bases away. The vast number of mutations associated with skin color and the uncertainty surrounding the target genes regulated by these mutations make it particularly arduous for researchers to find the precise genetic mechanisms governing this trait.

Feng and collaborators used massively parallel reporter assays to discern the regulatory activities of thousands of variants. This high-throughput technique narrowed down the thousands of candidates to 165 functional variants. To identify the target genes of these functional variants, Feng further constructed high-resolution chromatin interaction maps in melanocytic cells using chromatin conformation capture assays. "This is a high-resolution 3D genome map in melanoma cells that will be valuable for gene regulation studies in pigmentation and melanoma biology," Feng says.

Using CRISPR/Cas9-based genome editing, the researchers discovered that mutations in an enhancer of OCA2, a gene associated with albinism, could lead to a 75% reduction in melanin levels when compared to control cells. Within the same OCA2 enhancer, the researchers identified two closely located regulatory variants, estimated to be 1.2 million years old and 57 thousand years old, with the latter coinciding with the period of human migration from Africa.

"This case illustrates the continuous evolution of human skin color, and it's remarkable to observe the significant effects on skin pigmentation attributed to a single enhancer," Feng says.

San people have relatively lighter pigmentation compared to other African populations and possess the oldest genetic lineages in humans. While it is hypothesized that the light skin color of the San may result from adaptation to a southern African environment, the genetic underpinnings of this adaptation remain elusive. The researchers pinpointed several crucial regulatory variants near MITF , LEF1, and TRPS1 that contribute to the skin color adaptation observed in the San.

"MITF , LEF1, and TRPS1 are involved in signaling pathways regulating both melanocyte differentiation and hair development," Tishkoff says. "This suggests that the variants influencing the lighter skin pigmentation observed in the San people may also contribute to their distinctive hair morphology." Notably, the variant near TRPS1 associated with lighter skin color is at nearly 100% frequency in the San and in most non-Africans, whereas the variant associated with darker skin color is common in most other African populations and in the darkly pigmented Melanesian population, a striking example of global adaptations to UV exposure."

Additionally, the researchers found a novel gene impacting human skin pigmentation, CYB561A3, which regulates iron homeostasis and influences melanin levels in melanocytic cells. "To our knowledge, the role of CYB561A3 in skin pigmentation has not been reported before. Intriguingly, there have been reports linking intravenous iron infusion to skin hyperpigmentation. Given that CYB561A3 encodes an iron reductase, I am curious about the role of this protein in this process," Tishkoff says.

"Our findings underscore the complexity of genetic factors influencing skin color and the benefits of including ethnically diverse and underrepresented populations in genetic studies," she says. "Conducting functional studies on the impact of noncoding variants will enhance our comprehension of the genetics underlying complex human traits and disease risk."

"The populations included in this study are from remote regions of Africa and required the use of a mobile lab set up in the field sites," Tishkoff says. "The collaboration with our partners in Africa was key to the success of this research project."

In future research, the Tishkoff lab would like to use its innovative functional genomics approach to identify more genetic variants contributing to human pigmentation and other adaptive traits in a larger sample of ethnically diverse Africans.

Sarah Tishkoff is the David and Lyn Silfen University Professor in Genetics and Biology and a Penn Integrates Knowledge University Professor with appointments in the Perelman School of Medicine's Department of Genetics and Department of Medicine and in the School of Arts & Sciences' Department of Biology at the University of Pennsylvania.

Yuanqing Feng is a postdoctoral fellow in the Tishkoff lab at Penn.

Other authors include Ning Xie, Chao Zhang, Fang Zhang, and Matthew E.B. Hansen of Penn; Fumitaka Inoue of Kyoto University; Shaohua Fan of Fudan University; Thomas Nyambo of Hubert Kairuki Memorial University; Sununguko Wata Mpoloka and Gaonyadiwe George Mokone of the University of Botswana; Charles Fokunang and Alfred K. Njamnshi of the University of Yaoundé; Gurja Belay of Addis Ababa University; Michael S. Marks of the Children's Hospital of Philadelphia Research Institute; Elena Oancea of Brown University; and Nadav Ahituv of the University of California, San Francisco.

This research was supported by the National Institutes of Health (grants R35GM134957-01, 3UM1HG009408-02S1, 1R01GM113657-01, 5R01AR076241-02, and 1S10OD010786-01) and the Penn Skin Biology and Disease Resource-based Center (Grant NIH P30-AR069589).

• Human Biology
• Ozone Holes
• Earthquakes
• Sustainability
• Early Humans
• Human Evolution
• Public Health
• STEM Education
• Human skin color
• Molecular biology
• Malignant melanoma
• Skin grafting
• Stretch marks

Story Source:

Materials provided by University of Pennsylvania . Original written by Nathi Magubane. Note: Content may be edited for style and length.

Journal Reference :

• Yuanqing Feng, Ning Xie, Fumitaka Inoue, Shaohua Fan, Joshua Saskin, Chao Zhang, Fang Zhang, Matthew E. B. Hansen, Thomas Nyambo, Sununguko Wata Mpoloka, Gaonyadiwe George Mokone, Charles Fokunang, Gurja Belay, Alfred K. Njamnshi, Michael S. Marks, Elena Oancea, Nadav Ahituv, Sarah A. Tishkoff. Integrative functional genomic analyses identify genetic variants influencing skin pigmentation in Africans . Nature Genetics , 2024; DOI: 10.1038/s41588-023-01626-1

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