Mixed Race Studies

Why Is Skin Color Different? Huge Genetic Study Reveals Prevailing Theory of Pigmentation is Wrong

Newsweek
2017-11-30

Kastalia Medrano, Staff Writer

These are South African individuals in a household that exemplify the substantial skin pigmentation variability in the Khomani and Nama populations. Brenna Henn

Scientists used to think that the same small handful of genes accounted for about half of all pigment variation in human skin. A new study shows the genetic picture behind skin color is far more complex.

Research supporting the prior, simpler conclusion was skewed by Eurocentrism. Because it focused almost exclusively on Northern Eurasian populations from higher latitudes, the data missed a huge swath of the globe. Now, scientists have factored in people of color living in lower latitudes—and found that the prevailing theory is wrong.

Scientists from the Broad Institute of MIT and Harvard, Stanford University, and Stony Brook University worked with groups of indigenous southern African peoples called the KhoeSan, notable to some for their use of “click” language. They interviewed them, measured their respective heights and weights, and used a tool called a reflectometer to measure their skin pigmentation.

After seven years of research, and data gathered from about 400 individuals, the researchers realized that the closer a population lives to the equator, the greater the number of genes play a part in determining skin pigmentation. A paper describing the research was published November 30 in the scientific journal Cell.

“Previous work has shown the biomedical consequences of ethnically biased studies. Over the past 10 years, approximately 80 percent of genetic association studies were performed in European-descent groups,” Alicia Martin, a postdoctoral scientist in the lab of Broad Institute member Mark Daly, told Newsweek by email. “What we find here is that the biology of pigmentation or ‘architecture’ can be very different in Africans.” Martin says the findings emphasize the need to fund more genetic work in diverse populations…

Read the entire article here.

60th GRAMMY Awards: Full Nominees List

Grammys
Recording Academy
Santa Monica, California
2017-11-28

Find out who is nominated for the 60th GRAMMY Awards in New York on Jan. 28

The nominations for the 60th GRAMMY Awards are here! Find out who has been nominated in each of the 84 categories below (use the links to jump to a desired field).

…32. Best Jazz Vocal Album
(For albums containing at least 51% playing time of new vocal jazz recordings.)…

…Bad Ass And Blind
Raul Midón…

Read the entire article here.

Racial (Dis)Harmony: The Overestimated Post-racial Power of Meghan Markle

Bitch Media
2017-12-01

Dr. Shantel Gabrieal Buggs, Assistant Professor of Sociology and African American Studies
Florida State University

Photo credit: Twitter/newsjsBW

This week, the engagement of American actress Meghan Markle to British royal Prince Harry set social media ablaze.

Race is at the center of this internet firestorm: Markle is biracial, with a Black mother and white father. As a Black and white mixed-race woman who studies multiracial identity and interracial relationships, the online debates over Markle and her fiancé have been both perplexing and unsurprising. Over the last year, Markle’s racial background has drawn negative press in Britain. Last November, Prince Harry publicly called out the barely veiled racism and sexism in the media coverage of their relationship. Despite this treatment, their engagement is viewed as an opportunity to change what it means to be British and royal, with American fans celebrating a “real Black princess” who will bring #BlackGirlMagic to the royal family and the seemingly stale royal wedding traditions. Several essays have been written about what Markle’s presence means for the British monarchy and the broader racial politics of the West…

Read the entire article here.

Loci associated with skin pigmentation identified in African populations

Science
2017-10-12
eaan8433
DOI: 10.1126/science.aan8433

Nicholas G. Crawford, Derek E. Kelly, Matthew E. B. Hansen, Marcia H. Beltrame, Shaohua Fan, Shanna L. Bowman, Ethan Jewett, Alessia Ranciaro, Simon Thompson, Yancy Lo, Susanne P. Pfeifer, Jeffrey D. Jensen, Michael C. Campbell, William Beggs, Farhad Hormozdiari, Sununguko Wata Mpoloka, Gaonyadiwe George Mokone, Thomas Nyambo, Dawit Wolde Meskel, Gurja Belay, Jake Haut, NISC Comparative Sequencing Program, Harriet Rothschild, Leonard Zon, Yi Zhou, Michael A. Kovacs, Mai Xu, Tongwu Zhang, Kevin Bishop, Jason Sinclair, Cecilia Rivas, Eugene Elliot, Jiyeon Choi, Shengchao A. Li, Belynda Hicks, Shawn Burgess, Christian Abnet, Dawn E. Watkins-Chow, Elena Oceana, Yun S. Song, Eleazar Eskin, Kevin M. Brown, Michael S. Marks, Stacie K. Loftus, William J. Pavan, Meredith Yeager, Stephen Chanock, Sarah Tishkoff

Despite the wide range of skin pigmentation in humans, little is known about its genetic basis in global populations. Examining ethnically diverse African genomes, we identify variants in or near SLC24A5, MFSD12, DDB1, TMEM138, OCA2 and HERC2 that are significantly associated with skin pigmentation. Genetic evidence indicates that the light pigmentation variant at SLC24A5 was introduced into East Africa by gene flow from non-Africans. At all other loci, variants associated with dark pigmentation in Africans are identical by descent in southern Asian and Australo-Melanesian populations. Functional analyses indicate that MFSD12 encodes a lysosomal protein that affects melanogenesis in zebrafish and mice, and that mutations in melanocyte-specific regulatory regions near DDB1/TMEM138 correlate with expression of UV response genes under selection in Eurasians.

Variation in epidermal pigmentation is a striking feature of modern humans. Human pigmentation is correlated with geographic and environmental variation (Fig. 1). Populations at lower latitudes have darker pigmentation than populations at higher latitudes, suggesting that skin pigmentation is an adaptation to differing levels of ultraviolet radiation (UVR) (1). Because equatorial regions receive more UVR than temperate regions, populations from these regions (including sub-Saharan Africans, South Asians, and Australo-Melanesians) have darker pigmentation (Fig. 1), which likely mitigates the negative impact of high UVR exposure such as skin cancer and folate degradation (1). In contrast, the synthesis of vitamin D3 in response to UVR, needed to prevent rickets, may drive selection for light pigmentation at high latitudes (1).

The basal layer of human skin contains melanocytes, specialized pigment cells that harbor subcellular organelles called melanosomes in which melanin pigments are synthesized and stored and then transferred to keratinocytes (2). Melanosome morphology and content differs between melanocytes that synthesize mainly eumelanins (black-brown pigments) or pheomelanins (pigments which range from yellow to reddish-brown) (3). Variation in skin pigmentation is due to the type and quantity of melanins generated, melanosome size, and the manner in which keratinocytes sequester and degrade melanins (4).

While over 350 pigmentation genes have been identified in animal models, only a subset of these genes have been linked to normal variation in humans (5). Of these, there is limited knowledge about loci that affect pigmentation in populations with African ancestry (6, 7).

Skin pigmentation is highly variable within Africa

To identify genes affecting skin pigmentation in Africa, we used a DSM II ColorMeter to quantify light reflectance from the inner arm as a proxy for melanin levels in 2,092 ethnically and genetically diverse Africans living in Ethiopia, Tanzania, and Botswana (table S1 and figs. S1 and S2) (8). Skin pigmentation levels vary extensively among Africans, with darkest pigmentation observed in Nilo-Saharan speaking pastoralist populations in Eastern Africa and lightest pigmentation observed in San hunter-gatherer populations from southern Africa (Fig. 2 and table S1)…

Read the entire article here.

“She’s not exotic. She’s not from a tribe in the Amazon. She’s American”: Gina Yashere on Meghan Markle’s engagement

Channel 4 News
London, United Kingdom
2017-11-28

Cathy Newman, Presenter

Interview with author Afua Hirsch and Charlie Brinkhurst-Cuff who is deputy editor of gal-dem – an online magazine written by women of colour. And from New York – the comedian Gina Yashere.

Skin pigmentation is far more genetically complex than previously thought

Broad Institute
Massachusetts Institute of Technology, Cambridge, Massachusetts
2017-11-30

David Cameron, Director of Communications/Media Relations

Credit : Brenna Henn South African individuals in a household that exemplify the substantial skin pigmentation variability in the Khomani and Nama populations. Picture taken with consent for publication.

By studying an African population underrepresented in most datasets, researchers find genetic complexity of pigmentation varies by latitude

Many studies have suggested that the genetics of skin pigmentation are simple. A small number of known genes, it is thought, account for nearly 50 percent of pigment variation. However, these studies rely on datasets that heavily favor northern Eurasian populations—those that reside mostly in higher latitude regions.

Reporting in the November 30 issue of Cell, researchers from the Broad Institute of MIT and Harvard, Stanford University, and Stony Brook University report that while skin pigmentation is nearly 100 percent heritable, it is hardly a straightforward, Mendelian trait. By working closely with the KhoeSan, a group of populations indigenous to southern Africa, the researchers have found that the genetics of skin pigmentation become progressively complex as populations reside closer to the equator, with an increasing number of genes—known and unknown—involved, each making a smaller overall contribution.

“Africa has the greatest amount of phenotypic variability in skin color, and yet it’s been underrepresented in large scale endeavors,” said Alicia Martin, a postdoctoral scientist in the lab of Broad Institute member Mark Daly. “There are some genes that are known to contribute to skin pigmentation, but by and large there are many more new genes that have not been discovered.”

“We need to spend more time focusing on these understudied populations in order to gain deeper genetic insights,” said Brenna Henn, assistant professor in the Department of Ecology and Evolution at Stony Brook University who, along with Martin, is a co-corresponding author…

Read the entire article here.

Being Irish, mixed race and living abroad: it’s complicated

The Irish Times
2017-12-01

Conrad Bryan, Treasurer
Irish in Britain

A scene from Hashtag Lightie, playing at the Arcola Theatre in north London.

London play ‘Hashtag Lightie’ puts the spotlight on mixed-race identity

I live in London, a melting pot of cultures and ethnicities. It is a place where anything goes and where people of different ethnicities have always mixed, loved and married.

However, today the binary black and white notion of race is being challenged by the younger generation. They are choosing for themselves where they sit on the colour spectrum and how they self-identify. No longer will they accept other people labelling them.

Many are choosing to self-identify as mixed-race rather than black, which is causing a real debate in the black community here. This has many consequences for individuals struggling to determine where they fit in society, or what side to take…

Read the entire article here.

An Unexpectedly Complex Architecture for Skin Pigmentation in Africans

Cell
Volume 171, Issue 6, 2017-11-30
pages 1340–1353.e14
DOI: 10.1016/j.cell.2017.11.015

Alicia R. Martin, Meng Lin, Julie M. Granka, Justin W. Myrick, Xiaomin Liu, Alexandra Sockell, Elizabeth G. Atkinson, Cedric J. Werely, Marlo Möller, Manjinder S. Sandhu, David M. Kingsley, Eileen G. Hoal, Xiao Liu, Mark J. Daly, Marcus W. Feldman, Christopher R. Gignoux, Carlos D. Bustamante, Brenna M. Henn

Highlights

• Skin pigmentation in Africans is far more polygenic than light skin in Eurasians
• Southern African KhoeSan populations have lighter skin compared to equatorial Africans
• Highly heritable KhoeSan skin color variation is poorly explained by known genes
• The study of African skin color identifies novel and canonical pigmentation genes

Approximately 15 genes have been directly associated with skin pigmentation variation in humans, leading to its characterization as a relatively simple trait. However, by assembling a global survey of quantitative skin pigmentation phenotypes, we demonstrate that pigmentation is more complex than previously assumed, with genetic architecture varying by latitude. We investigate polygenicity in the KhoeSan populations indigenous to southern Africa who have considerably lighter skin than equatorial Africans. We demonstrate that skin pigmentation is highly heritable, but known pigmentation loci explain only a small fraction of the variance. Rather, baseline skin pigmentation is a complex, polygenic trait in the KhoeSan. Despite this, we identify canonical and non-canonical skin pigmentation loci, including near SLC24A5, TYRP1, SMARCA2/VLDLR, and SNX13, using a genome-wide association approach complemented by targeted resequencing. By considering diverse, under-studied African populations, we show how the architecture of skin pigmentation can vary across humans subject to different local evolutionary pressures.

Read or purchase the article here.

Harry-and-Meghan is not ‘great news’ for interracial couples

gal-dem
2017-12-01

Natalie Morris

image via Vanity Fair

On Monday it was announced that Prince Harry is engaged to Meghan Markle – a half white, half black American. A mixed-race woman is about to become the first non-white member of the British monarchy, and I am conflicted.

Feelings about the Royal Family aside, my initial instinct was that the introduction of any kind of diversity to this country’s most historic institution can only be a good thing. There’s definitely a little girl inside me who wants to cry joyful tears at the thought of a black princess. But after about four minutes on Twitter and an avalanche of headlines screaming about Harry’s “exotic” choice of fiancée, I realised how this was actually going to go…

Read the entire article here.

Do Not Pass

Sunday Book Review
The New York Times
2010-02-16

Touré

This may come as a shock to you, especially if you look at whiteness as a boon and blackness as a burden, but I have never once wished to be white. If a fairy godfather came to me and said I could switch races, I’d open the window and make him use it. I think 99 percent of black people would do the same. That’s not a knock on whiteness — it seems to be working out well for many people — it’s that I love blackness, even if passing would allow me to unhook myself from the heavy anchor called racism. It’s cool: I’ve learned how to be as quick as a Br’er Rabbit, even with the anchor attached. Still, you might argue, wouldn’t switching from a disadvantaged race to the dominant one be as liberating as a winning lottery ticket? Well, for those who’ve been able to complete the sociopolitical fantasy trip and become racial transvestites, it usually ends badly.

The character who jumps the color line is a fascinating American rogue, a self-­constructed person, a trickster who’s discovered that race is not an unscalable wall but a chain-link fence with holes big enough for some people to slip through. But once they cross the line, they’re fugitives hiding in plain sight, on the lam from themselves and their histories, cut off from their families, unchained from racism but chained to a secret whose revelation would bring an end to a life built on lies and a stolen place in the dominant culture. All that makes racial shape-shifters a fantastic opportunity for a writer: they’ve got Huck Finn’s independence, an identity in turmoil, a secret that could destroy their world, a refusal to be defined by others and a vantage on race that very few ever get to have. And in the story of a racial fugitive, there’s always a ticking bomb. It’s a corollary of the literary law that if you put a loaded rifle onstage, it has to go off: if a character shifts races, eventually he’ll be unmasked, and usually it’s painful physically or psychically or both…

Read the entire article here.