Science has had a complicated history with the word “race.” In the 19th century, Dr. Samuel Morton believed humans could be divided into five races following a specific hierarchy of intelligence due to skull capacity (a line of thought now seen as the origin of scientific racism) (1). At its minimum, “race” was used to categorize humans into different subspecies. However, in modern ecology, genetic differentiation must be able to outline the groups representing each subspecies. When full human genomes were first sequenced and then compared to each other, scientists began to doubt that humans could be subdivided into different groups the way other organisms are.
This doubt was further realized when scientists considered the history of humans in comparison to our closest relative, the chimpanzee. In order for a species to evolve into two separate subspecies, the two groups must be unable to share genes for a long enough period of time to develop characteristics that make them distinct from one another (2). Most speciation arises due to geographic barriers separating the ancestors of a species and a small group that had deviated from the original location. Humans, however, are incredibly mobile and were able to surpass any potential geographic barrier between groups. In addition, most scientists concede that humans have not been on Earth nearly long enough to evolve into subspecies. For reference, humans evolved about 200,000 years ago while chimpanzees evolved over 5 million years ago (3).
In the end, the true test of this theory was our genetics. Scientists used DNA from both chimpanzees and humans from around the globe to determine if they could create a phylogenetic tree — in essence, a family tree showing evolutionary lineage — for each species. Both species were sampled with the same criteria such as differentiation threshold (how different the DNA from two samples must be from each other to signal a new subspecies) and sharp boundaries (such as differences in geographic location). The studies pointed to one major fact: unlike the chimpanzees, no “trademark” group of genetic differences could distinguish one major group of humans from another (4). In other words, chimpanzees could be subdivided into races, but humans could not.
Other studies finally debunked race as a biological marker for humans for two key reasons. One is that genetics do not show one single variant that could distinguish a “white” person, for example, from a “black” person. Skin color is determined by a number of genes, and so even if a certain combination of genes suggested someone may have dark skin, an entirely different combination could also lead to dark skin. In addition, humans are so mixed that any adaptive traits that may have arisen in isolation do not clearly “belong” to one group of people. Moreover, the traits we might see in a particular white person — blond hair, blue eyes, light skin — are not grouped together in our DNA. In other words, many characteristics that we consider as racial traits are inherited independently from each other. Having light skin has nothing to do with one’s having blue eyes (or being tall, or liking math, for that matter).
The other reason is that even when scientists are able to group human in quasi-distinct categories, the genetics reveal that their divisions do not line up with the social concept of race. In fact, there is more genetic diversity in Africa alone than in all other continents combined (5). Moreover, there is so much variation within one “race” that two random Italians are likely to be just as genetically different from each other as a Korean and an Italian (6).
Still, people and some scientists alike, continue to hold onto the idea that race is linked to inherited traits. If race has no biological grounds, how can one explain why African American women in the United States are more likely to die from breast cancer than Caucasian women? Or that Native Americans have the highest rates of diabetes (7)?
A true comparison between these different categories of people would require, like all scientific experiments, a controlled environment (which in many cases may not be ethically or practically possible). Every individual would need to have the same access to Medicare, health insurance, and living conditions of the same quality. Without these controls, no conclusions can be drawn about an individual’s innate or genetic affinity for certain medical outcomes (8).
So if racial groups provide very weak proxies for genetic diversity, should the idea of race be phased out altogether? Well, maybe not. Scientists continue to use race as an experimental variable, but not for the reasons that one might expect. A doctor running a clinical trial should not make medical predictions based on a person’s race because his or her assumptions could lead to errors such as cystic fibrosis being underdiagnosed in African Americans due to misconceptions about its being a “white” disease (9). This doctor should, however, consider the social conditions in which their patient’s race might have subjected him/her to, such as living conditions, medical history, life stresses, etc. Discrimination does produce disparities in health, so making sure experiments and clinical trials include equal representation may produce more generalizable results.
What about phasing out race beyond scientific scenarios? While the different races in which humans are categorized have no biological basis, race — the word itself — should not yet be eliminated from our vocabulary. Race is a construct based largely on skin color and, in some cases, language and geographical location, that has affected countless of individuals and groups throughout history and present day. Simply ignoring race because we know it is man-made is not the same thing as finding equality.
Striving for a colorblind society can be counterproductive if it leads to avoiding topics related to racism instead of responding to them. Labels like race give credit to those individuals who needed to travel further in order to reach the same finish lines as their more privileged peers. In fact, recognizing race and that it has no biological grounds could be the first step towards addressing the social factors that have allowed racial discrimination and inequality to persist. Yes, our diversity and individuality come from differences in our DNA. But it is we, the people, who can make a difference in our world.