Improvements in the data have resulted in many people noticing changes in their ethnic mix from when they first took their ancestry-based DNA test. While the science of ancestry is still in its infancy, some are already asking questions the DNA tests can’t yet answer:
- Does the global ease of travel and increased migration mean there will be new ethnic groups that might exist in the future?
- Will these same factors lead to having ethnic groups that might go extinct in the future?
- Will genetic intermixing mean people will start to look more alike?
The Life’s Little Mysteries web site presented the notion that humans will one day homogenize and, over a few centuries, “we’re all going to look like Brazilians.” Stephen Stears, the Edward P. Bass Professor of Ecology and Evolutionary Biology at Yale University, told the web site that globalization, immigration, ease of modern travel and cultural diffusion will average out more and more people’s traits. Stearns noted that the invention of the bicycle vastly increased the average distance that men went looking for wives.
“The distance between the birthplaces of parents has continued to increase since the invention of the bicycle, making it now easy, if not standard, for parents to have been born on different continents,” Stearns said.
In the United States, a lessening tendency for people to mate within their own ancestral group might be the explanation for a reduction in the prevalence of blue-eyed individuals in the overall population. Epidemiologist Diane Lauderdale told Life’s Little Mysteries that only 1 in 6 non-Hispanic white Americans had blue eyes in a 2002 study. A century ago, about half the white population had blue eyes.
Traits that are common in people with northern European heritage will be seen less often, due to an immigration influx of people from Asia, Africa, and Latin America, evolutionary biologist John McDonald told the web site. “Examples would include red and blond hair blue eyes and freckles,” he said. “Traits that are recessive and are more common in some groups than others will decrease due to blending: blue eyes, sickle cell anemia, and cystic fibrosis are examples of this.”
Will There be New Races That Might Exist in the Future?
Across some quarters of social media, such as YouTube and Reddit, there is speculation that ongoing genetic mixing brought on by migration and travel will result in the creation of new races such as “Euro-African” or “Afro-Asian.” What about that? Will we see new races, or lose some that have existed for many centuries? This genetic intermixing concept isn’t new. It gets complicated, though, because it drifts a bit from the arena of genetic science into anthropology, sociology and even global politics.
Merriam-Webster defines race as “a category of humankind that shares certain distinctive physical traits.” It also defines race as “a family, tribe, people, or nation belonging to the same stock.” While such descriptors have served their purposes over the centuries, they have become fraught with difficulty in the 21st century. It begs some immediate questions:
- Who decides what the ‘race’ groupings are?
- Can such groupings be used to discriminate against people?
- Does the term encourage stereotyping, bias and prejudice?
Many will argue that race is a subjective social construct not based on biological science. “All human genomes are 99.5 percent identical, and although it’s true that the remaining 0.5 percent can vary in ways that correlate with geographical ancestry, these correlations do not strictly map to racial categories,” wrote Tim Requarth in Slate magazine. “If you hand a scientist your genome, she might be able to tell you something about the geographical distribution of your ancestors, but she cannot tell you what race you are. There’s simply nothing in the genome that’s an unambiguous marker of race.”
Recent human history is replete with examples of how so-called race science has been used to justify discrimination and atrocities, such as Adolf Hitler’s maniacal drive to create a master race. While attitudes about race and how the term is applied have changed, there is still plenty of controversies. James Watson, the pioneering scientist who helped discover the structure of DNA in 1953, created a furor in 2007 by suggesting that intelligence is tied to race. Watson apologized but later admitted in a documentary that his views on the matter had not changed.
Socially defined, the race is an “arbitrarily organized combination of physical traits, geographic ancestry, language, religion and a variety of other cultural features,” says Joseph L. Graves, a Professor of Biological Sciences at the Joint School of Nanoscience & Nanoengineering in Greensboro, N.C. Graves said the consensus of evolutionary biologists is that humans don’t have enough genetic variability to justify geographically-based races or evolutionary distinct lineages.
“It is true that all modern human populations have genetic differences that reflect adaptation to the environments their “recent” ancestors inhabited,” Graves wrote in Teaching Tolerance magazine. “There are also genetic changes that resulted from simple chance events.” Humans descended from people native to East Africa, only began to migrate and populate the rest of the globe some 60,000 years ago, he said. Some biological traits that are not found today in sub-Saharan Africans, such as fair skin and blue eyes, are at most 6,000 years old.
Graves said there is simply “no single physical trait or gene that can be used to unambiguously assign people to racial groups.” For example, skin color is associated with solar intensity, so “all populations with tropical ancestry have darker skin than those whose recent ancestry is from the temperate and arctic zones.”
Studying DNA can estimate the continental origin of DNA segments, Graves said, but “no single genetic marker is going to be a reliable estimate of ancestry, so statistical methods such as maximum likelihood are used to make estimates of a person’s ancestry.”
The American Association of Physical Anthropologists released a position paper in 2019 making the same point. “The groupings of people that exist in our species are socially-defined, dynamic, and continually evolving — amalgamations of socially- and biologically-interacting individuals with constantly-shifting boundaries, reflecting the myriad ways that individuals, families, and other clusters of people create ties, move, trade, mate, reproduce, and shift their social identities and affiliations through time,” the group wrote, according to The New York Times. “Race does not capture these histories or the patterns of human biological variation that have emerged as a result. Nor does it provide a clear picture of genetic ancestry.”
A Little History
So where did the idea of the entire population becoming “one race” or one ethnicity originate? The larger concept can be viewed in the history of the United States. The Great Seal of the United States depicts a bald eagle carrying a banner that reads E Pluribus Unum, which is Latin for “Out of Many, One.” The motto on the seal, adopted in 1782, referred to the union of the original 13 United States. The term came to represent the larger ideal of America: from many peoples and backgrounds, one nation. The country has long been described as a great “melting pot,” where immigrant peoples from around the world come together and become assimilated as Americans.
“So the United States steadily evolved to define Americans by their shared values, not by their superficial appearance,” historian Victor Davis Hanson of the Hoover Institution writes. “Eventually, anyone who was willing to give up his prior identity and assume a new American persona became American. The United States has always cherished its ‘melting pot’ ethos of E Pluribus Unum — of blending diverse peoples into one through assimilation, integration, and intermarriage.” Hanson described this longstanding phenomenon as “multiracialism under one common culture.” That has in recent times been replaced by multiculturalism, “in which each particular ethnic group retained its tribal chauvinism and saw itself as separate from the whole.” This movement starts to swing the pendulum back to a time when segregation was common and mixing was discouraged — or banned.
Ideals often have not matched practice when it comes to the notion of “race.” In the 1860s, the term “miscegenation” was coined, from the Latin miscere (to mix) and genus (race). Laws and practices that enslaved and discriminated against wide swaths of people based on their skin color have scarred American history. The bloody Civil War of 1861-1865 was fought to keep the United States from being ripped in two by the issue of race and slavery.
A book published in New York in 1864 purported to encourage racial intermixing as “indispensable to progressive humanity” and teach that “a people, to become great, must become composite.” These words, which by modern standards sound rather upright, were actually a hoax. They were written by a Democrat newspaperman who hoped to stir resentment against his political opponents, the Republicans, who ostensibly held views more friendly to miscegenation. Written anonymously, the book was eventually linked to David Goodman Croly of the New York World. Croly mailed a copy of the book to U.S. President Abraham Lincoln, hoping he could discredit the abolition movement to end slavery.
Anti-miscegenation laws became commonplace in the United States and lasted into a fairly recent history. Even when laws prohibiting or discouraging intermixing were abolished, social taboos remained a force. A number of other countries had similar edicts, such as Germany’s Nuremberg laws that banned marriage or sexual relations between Aryans and non-Aryans (primarily Jews). South Africa enacted a ban on mixed marriages in 1949 and forbid sexual relations between whites and non-whites. Those laws were abolished in the mid-1980s. These are just some examples of how a socially defined division of people based on traits can lead to bias, bigotry — and even worse. They also help explain why many researchers today eschew the notion of race as not biologically based and fraught with moral and political issues.
Ethnicity and Origins
If race is not a scientifically accurate concept, what exactly do the millions of DNA tests sold in recent years tell us about the population? The major test vendors talk about “ethnicity” or “ancestry,” but even those terms are not used or even defined uniformly. Well-known test vendor 23andMe tests DNA to discover links across more than 1,500 geographic regions. AncestryDNA tests for more than 1,000 regions. Both vendors’ tests can estimate to a country-specific or regional level. As we discuss later in the article, these companies are striving to improve results for customers with ancestral ties to Africa, Asia, and the Middle East, and in so doing, reduce the heavy European concentration in test samples.
A quick glance across the two companies’ ancestry/origins reports shows what you might expect: diversity. Here’s just a sampling:
- Cameroon, Congo & Southern Bantu
- African American
- Indigenous Arctic
- Indigenous Americas
There are no simple, easy answers when we try to define and categorize people just using physical traits or regional geography. The truth is, humans are both the same — and very different. “So, modern genomic science is increasing our appreciation of the uniqueness of the genetic blueprints that build wonderfully individual human beings,” Bob Grant wrote in The Scientist. “We’re different. At the same time, cutting-edge research is reinforcing the fact that we humans share a remarkable similarity in our DNA. We’re the same.”
Care must be taken, Grant said, in how we use the growing knowledge of sameness and differences that come from DNA studies and other scientific inquiry. “To ensure that they do not repeat the shameful misuse of science that plagued the study of human genetics in decades past, researchers must communicate the unfurling genomic landscape in a way that is clear and accurate,” Grant said.
“Doing so will help science and medicine incorporate this complexity and use it to everyone’s advantage. And painting a factual picture of our genetic commonalities and differences can ultimately assist humanity in celebrating both the ties that bind us and the uniqueness that makes each of us (at least potentially) wonderful.”
Factors in Ethnicity
Population migration has been going on to varying degrees for tens of thousands of years. As people moved from East Africa to populate the continents, regional differences developed based on climate, solar intensity, altitude, food supply, and other factors. As populations settled, ethnic groups developed, based on shared language, customs, and traditions.
The kind of large-scale migration that can lead to genetic mixing occurred throughout the last half of the 19th century. Driven by religious persecution and chronic famine at home, millions of Irish, Germans and other peoples moved from Europe to the United States. They were drawn by stories of freedom, inexpensive homestead land, and availability of factory jobs and other opportunities. Still, these groups maintained their ethnic identities and self-segregated in housing and places of worship. It took generations for these cultural bonds to loosen.
In modern times, migration is driven more by the ease and low cost of travel and a global economy with its demands for high-skill workers. Will this lead to the “everyone looks alike” homogeneity, the creation of new ethnic identities, or simply more genetic diversification?
Proponents of the idea that we will all blend into the same look or skin tone simply misunderstand how genetics works, according to one geneticist. “The average human, using common sense philosophy, observes that the offspring of two parents are a mix of the characteristics of the parents,” said Razib Khan, a private-sector geneticist who writes for the Gene Expression blog. “This is correct as far as it goes, but from this many assume that characteristics are being blended together. This is not what is occurring.”
Genes simply don’t blend, he said. “Genes are discrete units of heredity: they do not blend, but preserve a full range of potential variation from generation to generation,” Khan wrote in Aero magazine. “Variation does not disappear because the genes do not disappear. They rearrange.”
So if there is an increase in mixed heritage, it won’t result in new “races,” but it could result in some different physical features that are not as common today, Khan said. As an example, he said, would be a person with richly curly blond hair, deep olive skin, and almond-shaped eyes. Not a new race or even ethnicity, but another in a range of looks.
“Looking forward into time, the science of genetics tells us that the full range of human physical expression will still exist, even if the fractions change because the underlying genetic variation will persist,” he said. “Some people will be such that we recognize them as white, or black or Asian. Many more will be unrecognizable combinations thereof. Science tells that the beige future will never arrive because there are no genes for beingness. Beige is simply one expression of genetic variation among many.”
DNA Tests: A Caution — and Some Improvements
Some scientists caution that the heavily marketed direct-to-consumer DNA tests often oversimplify ethnicity estimates. They are also somewhat in flux, as DNA companies expand the reference panels they use to estimate genetic ancestry.
“Genetic ancestry tests also tend to equate present-day peoples and contemporary patterns of genetic variation with those that existed in the past, even though they are not identical,” geneticist Jennifer Raff wrote in The New York Times. “In this regard, ancestry tests often oversimplify and misrepresent the history and pattern of human genetic variation, and do so in ways that suggest more congruence between genetic patterns and culturally-defined categories than really exists.”
The tests also offer more detailed results for those of European ancestry. So far it has proven more difficult to obtain good reference data on Asians, Africans and indigenous peoples. “Right now, it’s not possible to infer the exact sources of ancestry of African Americans,” said Sarah Tishkoff, a professor at the University of Pennsylvania who has studied African genomics, “and it would be unfortunate if they have the expectation that they will be able to get that information.” She told PC World magazine that there needs to be more resources devoted to generating this data.
The DNA-testing industry has been working to improve those areas.
AncestryDNA boosted the size of its reference panel from 16,600 people to 40,017. These reference samples divide the globe into 60 overlapping regions and groups. “A reference panel is made up of people with a long family history in one place or as part of one group,” AncestryDNA explains on its web site. “To make it into the AncestryDNA reference panel, these folks need two things. First, they need a paper trail that proves their family history. Then, they must have their ethnicity confirmed at the DNA level. It is not easy to make it into the panel! To tell your DNA story, we compare your DNA to the people in the reference panel and look for DNA you share.”
AncestryDNA has 535 DNA reference samples for Cameroon, Congo and the Southern Bantu people, 915 for China, 55 for Ethiopia and Eritrea, 109 for Ghana, 197 for Korea, 58 for Mongolia and Central Asia-North, 123 for Northern Africa and 413 for Northern and Western India. AncestryDNA has more than 15 million customer DNA samples in its total database. The larger and more diverse reference panel strengthens results generated for ancestry origins reports, and many customers have seen their original DNA reports change as the data became richer.
The 23andMe ancestry reports were recently improved to include new populations in South Asia, North Africa and western Asia. It was the second upgrade to the data in less than a year, providing more detailed results for customers in those regions. For example, the “Broadly South Asian” population is now broken down to Central Asian, Northern Indian & Pakistani, Bengali & Northeastern Indian, Gujarati Patidar, Southern Indian Subgroup, Southern Indian & Sri Lankan, and Malayali Subgroup. The company also expanded populations in North Africa and Western Asia to eight groups: Peninsular Arab, Levantine, Egyptian, Coptic Egyptian, North African, Cypriot, Anatolian, and a population called “Iranian, Caucasian & Mesopotamian,” 23andMe reports on its web site.
The data improvements have come in large part from 23andMe’s Global Genetics Project, which is recruiting reference panel members with genetic ties to a wide range of countries, from Nepal and Oman to Somalia and Sudan.
The “data diversity” issue extends well beyond the world of direct-to-consumer DNA tests. Research databases of DNA samples are also weighted very heavily to European populations. This was in part because of how and where the DNA technology developed, but scientists acknowledge the urgency of improving the global diversity of study samples. That work is ongoing.
“People whose lineages are well represented in genomic databases will benefit the most from precision medicine approaches that rely on genetic markers to diagnose, understand, and treat a patient’s disease,” Charles Lee wrote in The Scientist. “Individuals from underrepresented ethnicities are more likely to get inaccurate diagnoses from genetic tests, which may have negative consequences.”
A study that could help rectify the problem was announced at the American Society of Human Genetics conference in Texas. “Africa is the cradle of human genetic variation; yet, to date, genomic studies in African populations have mostly focused on common variation in small, geographically-limited groups,” read a summary of the study, whose primary author is Neil A. Hanchard of the Department of Molecular & Human Genetics at the Baylor College of Medicine.
A consortium of scientists did whole-genome sequencing of 426 people from 13 African countries and 50 ethnolinguistic groups. The new genome sequences filled in some of the routes that people took out of East Africa. What they found added detail to the southern migration of the Bantu people, and showed migration from East Africa to central Nigeria, according to a report in the Genetic Literacy Project. Scientists also found dozens of genes that affect the body’s immune response to viral infection, according to GLP. This information will be used in precision medicine to reveal the basic characteristics of genetic structures.
“When you consider which forces have shaped the genetic diversity of Africans, you tend to think of mosquito-transmitted diseases like malaria,” Hanchard said. “Our study suggests that viral infections have also helped to shape genomic differences between people and groups, via genes that affect individuals’ disease susceptibility.”
The gold mine of information contained in these 426 newly sequenced genomes could be good news for the companies that market ancestry-focused DNA tests. It could give a boost to the reference samples for African populations, meaning richer and more accurate ethnicity estimates. “More genome information promises to fill in some gaps,” said Ricki Lewis, a Ph.D. geneticist who writes for the Genetic Literacy Project.
We might not see a profusion of “new races” hundreds of years down the road. But this type of scientific inquiry should mean that we will better understand the genetic makeup, changing traits, shared history and inner workings of more people from across the globe.
That might just bring our descendants all a little closer.