Mixed Race Studies

The Franklin Institute Speaker Series: Does Race Exist? (9/12/18)

The Franklin Institute
Philadelphia, Pennsylvania
2018-09-13

On September 12, 2018, as part of The Franklin Institute Speaker Series, University of Pennsylvania professors Sarah Tishkoff and Dorothy Roberts joined The Franklin Institute’s chief bioscientist Jayatri Das for a program titled “Does Race Exist? Exploring the Future of Genetics, Ancestry, and Medicine.”

Skin Color and the Nature of Science

The American Biology Teacher
Volume 80, Number 3 (March 2018)
page 163
DOI: 10.1525/abt.2018.80.3.163

Douglas Allchin, Lecturer, History of Science and Technology
Minnesota Center for the Philosophy of Science
University of Minnesota

Skin color is the trait most commonly associated with race. Consider just the “black” in the Black Lives Matter name or the “white” in white nationalist rallies. Skin color and the concept of race are ideologically charged—and socially divisive. But scientifically, what is the nature of this relationship?

A study led by Sarah Tishkoff published not long ago in Science contradicts many widespread views of skin color and further dispels the very concept of human races in biology. The group identified at least eight genes for skin color, but the genes do not cluster neatly into predictable groups, or races. They further found that the genes do not align with conventional racial groups:

• The same depigmentation gene that led to “white” skin in the lineage of most Europeans (SLC24A5) is also common in East Africa, where skin color is much darker.
• Another pair of genes linked to lighter skin, hair, and eye color among Europeans actually originated in Africa, where among the San people in southern Africa, it also contributes to lighter skin tones.
• By contrast, a gene for darker pigmentation now common in Africa appears to be widespread in non-African groups as well: Indians, Melanesians, and Australian Aborigines.
• Some darker skin colors result not by increasing dark pigments but by reducing yellow and red pigments.

The routes to skin color are many and varied, and not exclusively determinant of any geographic or ancestral group. Trying to define race by skin color genetics is hardly “black and white.”…

Read the entire article here.

There’s No Scientific Basis for Race—It’s a Made-Up Label

National Geographic
April 2018 (The Race Issue)

By Elizabeth Kolbert
Photographs by Robin Hammond

The four letters of the genetic code —A, C, G, and T—are projected onto Ryan Lingarmillar, a Ugandan. DNA reveals what skin color obscures: We all have African ancestors.

It’s been used to define and separate people for millennia. But the concept of race is not grounded in genetics.

In the first half of the 19th century, one of America’s most prominent scientists was a doctor named Samuel Morton. Morton lived in Philadelphia, and he collected skulls.

He wasn’t choosy about his suppliers. He accepted skulls scavenged from battlefields and snatched from catacombs. One of his most famous craniums belonged to an Irishman who’d been sent as a convict to Tasmania (and ultimately hanged for killing and eating other convicts). With each skull Morton performed the same procedure: He stuffed it with pepper seeds—later he switched to lead shot—which he then decanted to ascertain the volume of the braincase.

Morton believed that people could be divided into five races and that these represented separate acts of creation. The races had distinct characters, which corresponded to their place in a divinely determined hierarchy. Morton’s “craniometry” showed, he claimed, that whites, or “Caucasians,” were the most intelligent of the races. East Asians—Morton used the term “Mongolian”—though “ingenious” and “susceptible of cultivation,” were one step down. Next came Southeast Asians, followed by Native Americans. Blacks, or “Ethiopians,” were at the bottom. In the decades before the Civil War, Morton’s ideas were quickly taken up by the defenders of slavery…

Skulls from the collection of Samuel Morton, the father of scientific racism, illustrate his classification of people into five races—which arose, he claimed, from separate acts of creation. From left to right: a black woman and a white man, both American; an indigenous man from Mexico; a Chinese woman; and a Malaysian man. Photograph by Robert Clark PHOTOGRAPHED AT PENN MUSEUM

…By analyzing the genes of present-day Africans, researchers have concluded that the Khoe-San, who now live in southern Africa, represent one of the oldest branches of the human family tree. The Pygmies of central Africa also have a very long history as a distinct group. What this means is that the deepest splits in the human family aren’t between what are usually thought of as different races—whites, say, or blacks or Asians or Native Americans. They’re between African populations such as the Khoe-San and the Pygmies, who spent tens of thousands of years separated from one another even before humans left Africa…

Read the entire article here.

The study adds to established research undercutting old notions of race. You can’t use skin color to classify humans, any more than you can use other complex traits like height, [Sarah] Tishkoff says. “There is so much diversity in Africans that there is no such thing as an African race.”

Ann Gibbons, “New gene variants reveal the evolution of human skin color,” Science, October 12, 2017. http://www.sciencemag.org/news/2017/10/new-gene-variants-reveal-evolution-human-skin-color.

New gene variants reveal the evolution of human skin color

Science
2017-11-12

Ann Gibbons, Contributing Correspondent

Researchers have identified genes that help create diverse skin tones, such as those seen in the Agaw (left) and Surma (right) peoples of Africa. ALESSIA RANCIARO & DR. SIMON R. THOMPSON

Most people associate Africans with dark skin. But different groups of people in Africa have almost every skin color on the planet, from deepest black in the Dinka of South Sudan to beige in the San of South Africa. Now, researchers have discovered a handful of new gene variants responsible for this palette of tones.

The study, published online this week in Science, traces the evolution of these genes and how they traveled around the world. While the dark skin of some Pacific Islanders can be traced to Africa, gene variants from Eurasia also seem to have made their way back to Africa. And surprisingly, some of the mutations responsible for lighter skin in Europeans turn out to have an ancient African origin.

“This is really a landmark study of skin color diversity,” says geneticist Greg Barsh of the HudsonAlpha Institute for Biotechnology in Huntsville, Alabama.

Researchers agree that our early australopithecine ancestors in Africa probably had light skin beneath hairy pelts. “If you shave a chimpanzee, its skin is light,” says evolutionary geneticist Sarah Tishkoff of the University of Pennsylvania, the lead author of the new study. “If you have body hair, you don’t need dark skin to protect you from ultraviolet [UV] radiation.”

Until recently, researchers assumed that after human ancestors shed most body hair, sometime before 2 million years ago, they quickly evolved dark skin for protection from skin cancer and other harmful effects of UV radiation. Then, when humans migrated out of Africa and headed to the far north, they evolved lighter skin as an adaptation to limited sunlight. (Pale skin synthesizes more vitamin D when light is scarce.)…

Read the entire article here.

What Doctors Should Ignore

The New York Times
2017-12-08

Moises Velasquez-Manoff

Joan Wong

Science has revealed how arbitrary racial categories are. Perhaps medicine will abandon them, too.

Sickle cell anemia was first described in 1910 and was quickly labeled a “black” disease. At a time when many people were preoccupied with an imagined racial hierarchy, with whites on top, the disease was cited as evidence that people of African descent were inferior. But what of white people who presented with sickle cell anemia?

Doctors twisted themselves into knots trying to explain those cases away. White sickle cell patients must have mixed backgrounds, they contended — a black forebear they didn’t know about perhaps, or one they didn’t want to mention. Or maybe white patients’ symptoms didn’t stem from sickle cell anemia at all, but some other affliction. The bottom line was, the disease was “black,” so by definition white people couldn’t get it.

Today, scientists understand the sickle cell trait as an adaptation to malaria, not evidence of inferiority. One copy of the sickle cell trait protects against malaria. Having two can cause severe anemia and even death. Scientists also know that the trait is common outside Africa across the “malaria belt” — the Arabian Peninsula, India and parts of the Mediterranean Basin. And people historically considered white can, in fact, carry it. In the Greek town of Orchomenos, for example, the gene is more prevalent than it is among African-Americans.

We know all this, and yet the racialization of the disease, the idea that it occurs only in people of sub-Saharan African descent, persists. “When I talk to medical students, I get this all the time — ‘Sickle cell is a black trait,’ ” Michael Yudell, chairman of the department of community health and prevention at the Dornsife School of Public Health at Drexel University, told me.

That’s worrisome for many reasons, he says, chief among them that it may result in subpar medical care for some patients. Case in point: California’s universal blood disorder screening program has identified thousands of nonblack children with the sickle cell trait and scores with the disease — patients who, had doctors stuck to received “wisdom,” might have been missed.

Professor Yudell belongs to a growing chorus of scholars and researchers who argue that in science at least, we need to push past the race concept and, where possible, scrap it entirely. Professor Yudell and others contend that instead of talking about race, we should talk about ancestry (which, unlike “race,” refers to one’s genetic heritage, not innate qualities); or the specific gene variants that, like the sickle cell trait, affect disease risk; or environmental factors like poverty or diet that affect some groups more than others…

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.

Taking race out of human genetics and memetics: We can’t achieve one without achieving the other

OUPblog: Oxford University Press’s Academic Insights for the Thinking World
2016-03-23

Carlos Hoyt

Carlos Hoyt explores race, racial identity and related issues as a scholar, teacher, psychotherapist, parent, and racialized member of our society, interrogating master narratives and the dominant discourse on race with the goal of illuminating and virtuously disrupting the racial worldview. Carlos holds teaching positions at Wheelock College, Simmons College, and Boston University in Boston Massachusetts, and has authored peer-reviewed articles on spirituality in social work practice and the pedagogy of the definition of racism. He is the author of The Arc of a Bad Idea: Understanding and Transcending Race, published by Oxford University Press.

Acknowledging that they are certainly not the first to do so, four scientists, Michael Yudell, Dorothy Roberts, Rob Desalle, and Sarah Tishkoff recently called for the phasing out of the use of the concept/term “race” in biological science.

Because race is an irredeemably nebulous, confused, and confusing social construct, the authors advocate for replacing it with “ancestry.” “Ancestry,” they say, is a “process-based” concept that encourages one to seek information about genomic heritage, while race is a “patternbased” concept that induces one to organize individuals into preconceived hierarchical groupings based on shifting, murky, and contradictory combinations of appearance, geography, ability, worth, and the like.

If biological science seeks and relies on valid and maximally precise population level comparisons between groups, and race is an irrefutably imprecise proxy for consistent and concordant biological/genetic comparison, then of course we should stop using it in biology and switch over to “ancestry,” “genetic heritage,” or some other term that actually gets at what’s real, reliable, and useful. It doesn’t feel like a rocket-science proposition. And yet biological science hasn’t been able to heed the call and make the shift. And I sadly forecast that the shift won’t soon – or ever – be made – unless and until we take the step that even the well-meaning authors of this call for stop short of taking…

Read the entire article here.

Is It Time To Stop Using Race In Medical Research?

Shots: Health News from NPR
National Public Radio
2016-02-05

Angus Chen

Genetics researchers often discover certain snips and pieces of the human genome that are important for health and development, such as the genetic mutations that cause cystic fibrosis or sickle cell anemia. And scientists noticed that genetic variants are more common in some races, which makes it seem like race is important in genetics research.

But some researchers say that we’ve taken the concept too far. To find out what that means, we’ve talked to two of the authors of an article published Thursday in the journal Science. Sarah Tishkoff is a human population geneticist and a professor at the University of Pennsylvania. Dorothy Roberts is a legal scholar, sociologist and a professor at the University of Pennsylvania’s Africana Studies department. This interview has been edited for length and clarity…

Read entire interview here.

Taking race out of human genetics

Science
Volume 351, Issue 6273 (2016-02-05)
pages 564-565
DOI: 10.1126/science.aac4951

Michael Yudell, Associate Professor
Dornsife School of Public Health Department of Community Health and Prevention
Drexel University, Philadelphia, Pennsylvania

Dorothy Roberts, George A. Weiss University Professor of Law and Sociology and the Raymond Pace and Sadie Tanner Mossell Alexander Professor of Civil Rights
University of Pennsylvania

Rob DeSalle, Curator, Molecular Systematics; Principal Investigator, SICG Genomics Lab; Professor, Richard Gilder Graduate School
American Museum of Natural History, New York, New York

Sarah Tishkoff, David and Lyn Silfen University Professor in Genetics and Biology
University of Pennsylvania

In the wake of the sequencing of the human genome in the early 2000s, genome pioneers and social scientists alike called for an end to the use of race as a variable in genetic research (1, 2). Unfortunately, by some measures, the use of race as a biological category has increased in the postgenomic age (3). Although inconsistent definition and use has been a chief problem with the race concept, it has historically been used as a taxonomic categorization based on common hereditary traits (such as skin color) to elucidate the relationship between our ancestry and our genes. We believe the use of biological concepts of race in human genetic research—so disputed and so mired in confusion—is problematic at best and harmful at worst. It is time for biologists to find a better way.

Read the entire article here.