As a scientific concept – does race exist? Is it a useful construct, or is it more misleading than useful? I wrote about this question in 2016, and my thinking has evolved a bit since then. My bottom line conclusion has not changed – the answer is, it depends. There is no fully objective answer because this is ultimately a matter of categorization which involves arbitrary choices, such as how to weight different features, how much difference is meaningful, and where to draw lines. People can also agree on all the relevant facts, but disagree simply on emphasis. (If all of this is sounding familiar it’s because the same issues exist surrounding biological sex.)

Here are some relevant facts. Humans – Homo sapiens – are a single species. While we are an outbred species with a lot of genetic diversity, we have passed through several fairly recent genetic bottlenecks (most recently around 900k years ago) and the genetic disparity (amount of difference) among humans is relatively small (about 0.1%). It is also true that genetic variation is not evenly distributed among human populations but tend to cluster geographically. However, genetic variation within these clusters is greater than genetic variation between these clusters. Further, obvious morphological differences between identifiable groups tend to be superficial and not a good reflection of underlying genetic diversity. But at the same time, genetic background can be meaningful – predicting the risk of developing certain diseases or responding to certain medications, for example. Genetic variation is also not evenly distributed. Most genetic variations within humans is among Africans, because all non-Africans are derived from a recent genetic bottleneck population about 50-70k years ago.

How should we summarize all of these non-controversial and generally agreed upon facts? You can emphasize the clustering and say that something akin to race exists and is meaningful, or you can emphasize the genetic  similarity of all humans and lack of discrete groups to say that race is not a meaningful or helpful concept. So, as a purely scientific question we have to recognize that there is no completely objective answer here. There are just different perspectives. However, that does not mean that every perspective is equally strong or that our choice of emphasis cannot be determined by other factors, such as their utility in specific contexts.

But there is another dimension here – the term “race” has a specific history of use. It is a very loaded term, unlike, say, referring to “genetic clusterings” or terms we often use with reference to other species, like subpopulations or breeds.  The term race has a cultural history, generally referring to continent of origin. There is also a scientific history going back to Linnaeus, who thought there were four human races which he characterized by color – white, black, yellow, and red. Linnaeus’s “races” persisted in scientific thinking for two centuries, and still dominates our culture. When people say something like – “race does not exist” or “race is a social construct”, this is what they are referring to. It does not mean there are no genetic clusterings, just that the traditional races are not genetically meaningful. As one geneticist put it in a recent BBC article:

“By the time we began to look at how genes are shared in families and populations, we saw that similarities do indeed cluster in groups, but these groupings do not align with the longstanding attempts to classify the races. The true metric of human difference is at a genetic level. In the 20th Century, when we began to unravel our genomes, and observe how people are similar and different in our DNA, we saw that the terms in use for several centuries bore little meaningful relation to the underlying genetics.”

In medicine there is a very practical aspect to this discussion, because we use genetic history to help us estimate statistical risks in various medical contexts. Over my career we have moved away (admittedly, not entirely, cultural inertia can be strong) from characterizing patients or research subjects by race. This is not because it is politically incorrect, but because it is scientifically misleading. Instead we use a less specific term like “ancestry”. This is really just an extension of family history, which has long been a separate part of a patient’s history. We want to know the medical history of their immediate relatives because that can help us predict their disease risk. Ancestry is basically a “family” history but going back further, to successive ancestral clusterings (without favoring any particular level). Do you have ancestors who came from Africa? Do you have ancestors who were part of a founder population with a specific genetic illness?

Labeling someone as “black” or “caucasian” or “asian” is not genetically meaningful. There is nothing special about that level of clustering and these are not real or meaningful genetic groups. If you look, for example, at a genetic map, rather than skin color, you would never intuitively cluster humans into the traditional races.

But again, cultural inertia can be strong. From a science education and public understanding point of view perhaps we need to simply stop using the term race and instead refer to ancestry, or genetic populations or clustering. We should use language that properly reflects the scientific reality rather than the social history.

There is one more point of complexity, however. Sometimes we are having a social conversation. If race is a social construct, it has meaning in a social context (even if it is not scientifically meaningful). Identified race is a real social factor that influences people’s lives. So now we need to find a way to talk about genetic ancestry and social race as two distinct things, even though they were highly conflated in the past (and still in many people’s minds today). That’s a tricky one. Still probably best to dispense with the highly loaded term “race” and just come up with distinct terminology depending on whether your are discussing a social group or a genetic clustering.