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

Posted in Africa, Articles, Health/Medicine/Genetics, History, Media Archive on 2018-03-13 18:09Z by Steven

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

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Skin pigmentation, biogeographical ancestry and admixture mapping

Posted in Anthropology, Articles, Health/Medicine/Genetics, Media Archive, United Kingdom, United States on 2013-09-13 01:01Z by Steven

Skin pigmentation, biogeographical ancestry and admixture mapping

Human Genetics
Volume 112, Issue 4 (April 2003)
pages 387-399

Mark D. Shriver, Professor of Anthropology
Pennsylvania State University

Esteban J. Parra
Department of Anthropology
University of Toronto at Mississauga

Sonia Dios
Department of Anthropology
Pennsylvania State University

Carolina Bonilla
Department of Anthropology
Pennsylvania State University

Heather Norton
Department of Anthropology
Pennsylvania State University

Celina Jovel
Department of Anthropology
Pennsylvania State University

Carrie Pfaff
Department of Anthropology
Pennsylvania State University

Cecily Jones
National Human Genome Center
Howard University, Washington, D.C.

Aisha Massac
National Human Genome Center
Howard University, Washington, D.C.

Neil Cameron
Takeway Media, London

Archie Baron
Takeway Media, London

Tabitha Jackson
Takeway Media, London

George Argyropoulos
Pennington Center for Biomedical Research, Baton Rouge, Louisiana

Li Jin
Department of Environmental Health
University of Cincinnati, Cincinnati, Ohio

Clive J. Hoggart
Department of Epidemiology and Population Health
London School of Hygiene and Tropical Medicine

Paul M. McKeigue
Department of Epidemiology and Population Health
London School of Hygiene and Tropical Medicine

Rick A. Kittles
National Human Genome Center
Howard University, Washington, D.C.

Ancestry informative markers (AIMs) are genetic loci showing alleles with large frequency differences between populations. AIMs can be used to estimate biogeographical ancestry at the level of the population, subgroup (e.g. cases and controls) and individual. Ancestry estimates at both the subgroup and individual level can be directly instructive regarding the genetics of the phenotypes that differ qualitatively or in frequency between populations. These estimates can provide a compelling foundation for the use of admixture mapping (AM) methods to identify the genes underlying these traits. We present details of a panel of 34 AIMs and demonstrate how such studies can proceed, by using skin pigmentation as a model phenotype. We have genotyped these markers in two population samples with primarily African ancestry, viz. African Americans from Washington D.C. and an African Caribbean sample from Britain, and in a sample of European Americans from Pennsylvania. In the two African population samples, we observed significant correlations between estimates of individual ancestry and skin pigmentation as measured by reflectometry (R2=0.21, P<0.0001 for the African-American sample and R2=0.16, P<0.0001 for the British African-Caribbean sample). These correlations confirm the validity of the ancestry estimates and also indicate the high level of population structure related to admixture, a level that characterizes these populations and that is detectable by using other tests to identify genetic structure. We have also applied two methods of admixture mapping to test for the effects of three candidate genes (TYR, OCA2, MC1R) on pigmentation. We show that TYR and OCA2 have measurable effects on skin pigmentation differences between the west African and west European parental populations. This work indicates that it is possible to estimate the individual ancestry of a person based on DNA analysis with a reasonable number of well-defined genetic markers. The implications and applications of ancestry estimates in biomedical research are discussed.

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