Mixed Race Studies

Building a Face, and a Case, on DNA

The New York Times
2015-02-23

Andrew Pollack

The police in Columbia, S.C.,  released this sketch of a possible suspect based on DNA left at the crime scene. Parabon NanoLabs, which made the image, has begun offering DNA phenotyping services to law enforcement agencies.

There were no known eyewitnesses to the murder of a young woman and her 3-year-old daughter four years ago. No security cameras caught a figure coming or going.

Nonetheless, the police in Columbia, S.C., last month released a sketch of a possible suspect. Rather than an artist’s rendering based on witness descriptions, the face was generated by a computer relying solely on DNA found at the scene of the crime.

It may be the first time a suspect’s face has been put before the public in this way, but it will not be the last. Investigators are increasingly able to determine the physical characteristics of crime suspects from the DNA they leave behind, providing what could become a powerful new tool for law enforcement.

Already genetic sleuths can determine a suspect’s eye and hair color fairly accurately. It is also possible, or might soon be, to predict skin color, freckling, baldness, hair curliness, tooth shape and age.

Computers may eventually be able to match faces generated from DNA to those in a database of mug shots. Even if it does not immediately find the culprit, the genetic witness, so to speak, can be useful, researchers say…

…Law enforcement authorities say that information about physical traits derived from DNA is not permitted in court because the science is not well established. Still, the prospect of widespread DNA phenotyping has unnerved some experts.

Duana Fullwiley, an associate professor of anthropology at Stanford, said that she worried that use of such images could contribute to racial profiling. She noted that Dr. Shriver developed his system by analyzing the DNA and faces of people with mixed West African and European ancestry.

“This leads to a technology that is better able to make faces that are African-American,” she said. The image produced in the South Carolina case, Dr. Fullwiley added, “was of a generic young black man.”

Dr. Shriver said he initially studied people of mixed European and African ancestry, many of them from Brazil, because that made the analysis easier. His more recent research has involved people of many different ethnicities, he said…

Read the entire article here.

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.

Read the entire article here.

Estimating Genetic Ancestry Proportions from Faces

PLoS ONE
Volume 4, Number 2, e4460 (February 2009)
8 pages
DOI: 10.1371/journal.pone.0004460

Yann C. Klimentidis
Department of Biostatistics
University of Alabama, Birmingham

Mark D. Shriver, Associate Professor of Anthropology
Pennsylvania State University

Ethnicity can be a means by which people identify themselves and others. This type of identification mediates many kinds of social interactions and may reflect adaptations to a long history of group living in humans. Recent admixture in the US between groups from different continents, and the historically strong emphasis on phenotypic differences between members of these groups, presents an opportunity to examine the degree of concordance between estimates of group membership based on genetic markers and on visually-based estimates of facial features. We first measured the degree of Native American, European, African and East Asian genetic admixture in a sample of 14 self-identified Hispanic individuals, chosen to cover a broad range of Native American and European genetic admixture proportions. We showed frontal and side-view photographs of the 14 individuals to 241 subjects living in New Mexico, and asked them to estimate the degree of NA admixture for each individual. We assess the overall concordance for each observer based on an aggregated measure of the difference between the observer and the genetic estimates. We find that observers reach a significantly higher degree of concordance than expected by chance, and that the degree of concordance as well as the direction of the discrepancy in estimates differs based on the ethnicity of the observer, but not on the observers’ age or sex. This study highlights the potentially high degree of discordance between physical appearance and genetic measures of ethnicity, as well as how perceptions of ethnic affiliation are context-specific. We compare our findings to those of previous studies and discuss their implications.

Read the entire article here.

Michelle’s Great-Great-Great-Granddaddy—and Yours

The Root
2009-10-08

Henry Louis Gates Jr., Alphonse Fletcher University Professor and the Director of the W.E.B. Du Bois Institute for African and African American Research
Harvard University

First Lady Michelle Obama’s maternal third-great-grandfather was a white man who fathered Melvinia Shields’ (her maternal third great-grandmother) son, Dolphus T. Shields, both slaves. This discovery, like all recoveries of the identities of ancestors we thought had been obliterated in the crucible of slavery, is first and foremost a welcome gift for the first family, especially for Michelle’s mother, Marian Shields Robinson, and the Shields family line. And for anyone still naïve enough to believe in the myth of racial purity, it is one more corroboration that the social categories of “white” and “black” are and always have been more porous than can be imagined, especially in that nether world called slavery.

As I have learned since embarking upon my African American Lives series (for PBS), never before are more African Americans determined to ferret out the names of their slave ancestors, and never before have more resources, especially online, been available to facilitate these searches. But, be prepared. To paraphrase the Bible: seek; but fasten your seat belt as to what ye may find…

…African Americans, just like our first lady, are a racially mixed or mulatto people—deeply and overwhelmingly so. Fact: Fully 58 percent of African-American people, according to geneticist Mark Shriver at Morehouse College, possess at least 12.5 percent European ancestry (again, the equivalent of that one great-grandparent). As a matter of fact, if I analyzed the y-DNA (which a man inherits exactly from his father, and he from his father, etc.) of all the black players in the NBA, fully one-third (somewhere between 30 percent and 35 percent) would, incredibly, discover that they were descended from a white male who impregnated a black female, most likely a female slave, just as a white man did Michelle Obama’s third-great-grandmother. In the ‘60s, we were fond of saying that we are an “African people.” Well, our DNA proclaims loudly that we are a European people, a multicultural people, a people black as well as white. You might think of us as an Afro-Mulatto people, our genes recombined in that test tube called slavery…

Read the entire article here.