By Alondra Nelson

Tracing genealogy is now the second-most popular hobby amongst Americans. The tsunami of interest in genetic ancestry tracing from the African-American community has been especially overwhelming. It’s also the subject of professor of sociology Alondra Nelson’s The Social Life of DNA, in which she takes us on an unprecedented journey into how the double helix has wound its way into the heart of the most urgent contemporary social issues around race. In celebration of National DNA Day, we’re sharing this excerpt in which Nelson looks at the indubitable influence of Alex Haley’s Roots and the three broad classes of genetic ancestry services that have been developed since the start of this century.

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Genetic genealogy testing aligns with an enduring human desire: the search for roots and identity.

The appeal of genetic ancestry testing cannot be understood without also understanding the backdrop of the specific example author Alex Haley provided about how this should be accomplished and what effects it might produce. Roots, for which Haley received a Pulitzer Prize, tells the story of Haley’s colorful family genealogy, which he traces back to The Gambia. The story is framed as the author’s “epic quest”: his prodigious efforts across years and continents to uncover his family’s past. In 1977, when Haley’s work was transformed into a television miniseries, the story of his ancestors’ trials, tribulations, and resilience held the country in rapt attention for eight days.

Haley’s story came under scrutiny soon after it began to circulate, and was criticized for historical inaccuracies. He was accused of plagiarism on several occasions; one case would result in a settlement amount so large that it was effectively an admission of guilt. But these accusations did not present an obstacle to the story’s power, and the narrative remains a commanding cultural symbol, national script, and racial allegory.

Despite Haley’s heroic, if flawed, example, few African Americans are able to fill in the contours of their past as he did, owing to the decimation of families that was a hallmark of the era of racial slavery and the dearth of records from this period. As a consequence, genetic genealogy testing, which is now broadly available and also less taxing—and, owing to the social power of DNA, seemingly more authoritative—than conventional Haley-esque genealogical research, holds considerable appeal for many root-seekers.

Genetic genealogy testing emerged from techniques developed in molecular biology, human population genetics, and biological anthropology. Direct-to-consumer genetic testing was first available in the United States in 2000 from Family Tree DNA, a pioneer in this field that remains an industry leader. When African Ancestry was launched just a few years later, the company was as notable for joining the cutting edge of a new social and technical practice as it was for its niche mission and customer base. By 2004, five other American companies had joined the ranks of African Ancestry and Family Tree DNA. By 2010, thirty-eight companies worldwide offered an array of genetic-ancestry-testing services, with twenty-eight of these based in the United States.

The companies that sell DNA analysis for genealogical purposes offer three principal forms of analysis for which they create brand names, such as African Ancestry’s MatriClan and PatriClan. Rather than provide companies’ brand descriptions and for the sake of analytic clarity, here the tests will be classified by what information they provide as an end result to the consumer, because the forms of social orientation that the test results suggest are of primary importance to root-seekers. The genealogists I have spoken with purchased particular genetic tests in order to fulfill distinctive genealogical aspirations, such as corroboration of a multicultural background or association with an ethnic community. The three broad classes of DTC genetic ancestry services can be categorized as spatiotemporal analysis, racial-composite analysis, and ethnic-lineage analysis.

With spatiotemporal testing, a consumer’s DNA sample is classified into a haplogroup (sets of single nucleotide polymorphisms [SNPs] or gene-sequence variants that are inherited together) from which ancestral and geographical origins at some point in the distant past can be inferred. The result orients a consumer in space and time but does not provide identity per se. This form of analysis was made possible by the ambitious Y-DNA and mtDNA mapping research that resulted in theories about the times and places at which various human populations arose. Y-DNA and mtDNA have distinctive sequence combinations; similar sequences can be classified into broad groups, called haplogroups. Human population geneticists have devised a system of letters and numbers to identify the region of one’s ancestors, and also the time in history (hundreds of thousands of years ago) during which they would have migrated from Africa. Family Tree DNA, a forerunner in American genetic ancestry testing, supplies customers with haplogroup information, as does National Geographic’s Genographic Project. An inferred match with the mtDNA-derived L2a haplogroup—a designation shared by some of Venture Smith’s descendants—suggests that one’s ancestors lived in Africa approximately sixty thousand to eighty thousand years ago. In short, spatiotemporal analysis offers “deep” ancestry results that open a window onto the geographic past of ancestors who may have dwelled in a time and place far removed from where root-seekers presently abide.

Among the more spectacular claims of genetic ancestry testing is the ability to infer not merely where we come from but what we are, in the most essentialist sense. These tests, which I classify as racial-composite analysis, claim to ascertain the percentage of three of four supposedly “pure” racial groups. In contrast to spatiotemporal and ethnic-lineage analyses, which rely on mtDNA and Y-DNA, this genomics testing involves the analysis of nuclear or autosomal DNA, which is unique to each person (identical twins excepted, although this is now being debated) and consists of the full complement of genetic information inherited from parents. A DNA sample is compared with panels of proprietary SNPs that are deemed to be “informative” of ancestry. Algorithms and computational mathematics are used to analyze the samples and infer the individual’s “admixture” of three of four statistically constituted racial categories—African, Native American, East Asian, and European—according to the presence and frequency of specific genetic markers said to be predominate among but, importantly, not distinctive to, each of the “original” or “pure” populations.

This form of analysis was first developed by the DNA division of DNAPrint Genomics. When this Florida-based company launched in 2002, it offered the “first genomic ancestry test”; that is, a test based on complete autosomal DNA. A subject of this racial composite testing might learn he is estimated to be 80 percent African, 12 percent European, and 8 percent Native American. DNAPrint Genomics went out of business in 2009, but other companies offer similar services, including African Ancestry’s myDNAmix and 23andMe’s Ancestry Painting. This type of analysis proves useful to those who think that what we understand as racial groups are self-contained and, therefore, that mixture can be ascertained. However, it offers little guidance about one’s geographic or ethnic origins other than in the broadest sense. As African Ancestry cautions its customers on its website, “YOU WILL NOT LEARN COUNTRIES OR ETHNIC GROUPS.”

With ethnic-lineage testing, an individual’s DNA is searched against a genetic-ancestry-testing company’s reference database, which is in most cases proprietary, thus the claims made using it cannot be independently verified. (This is also true of the other types of analysis; DTC genetic testing companies hold data and algorithms as trade secrets.) A match between the sample and the reference DNA or shared haplotypes suggest a shared, distant maternal or paternal ancestor. Most companies offer this type of testing. A typical ethnic-lineage result may inform a test-taker that her mtDNA traced to the Mende people of contemporary southern Sierra Leone. Or a male customer could be inferred to be ancestrally linked to a group of male genealogists who share his surname and Y-DNA profile. African Ancestry’s analyses might thus be regarded as ethnic-lineage instruments through which an undifferentiated racial identity is translated into African ethnicity and kinship. By linking blacks to inferred ethnic communities and nation-states of Africa, African Ancestry’s service offers root-seekers the possibility of constituting new forms of identification and affiliation.

Each of these three types of tests thus offers a different window onto the past and, as Halbwachs would remind us, also a distinct vantage on the present. Root-seekers demonstrate their preferences for genetic information in the form of the testing they select and purchase. The usefulness of test results depends on the perspective of the root-seeker and the particular questions he or she seeks to answer through genetic genealogy analysis. In my encounters with genetic genealogists, one of the more important insights I gained is that root-seekers’ preferences are shaped by the problems to which they are applied. It should also be noted, however, that many of the test-takers I met used more than one type of genetic genealogy analysis, typically to compare results received from different companies or obtain new information from a company from which services were purchased previously (for example, when a company releases a more robust form of test that employs more markers or has added a significantly larger number of samples to its reference database).

About the Author 

Alondra Nelson is Dean of Social Science and professor of sociology and gender studies at Columbia University. She is author of the award-winning book Body and Soul: The Black Panther Party and the Fight Against Medical Discrimination and her writing has appeared in the New York Times, Washington Post, Science, Boston Globe, and the Guardian. She lives in New York City. Follow her on Twitter at @sociallifeofdna and visit her website.