Weekend Reads | A Closer Look at Genetic Research

by Kevin Schofield

This weekend, we're reading about genetics research, a rapidly progressing field with some unfortunate ties to backward, outdated ways of labeling groups of people.

Much of genetic research is about trying to link a "genotype," specific instructions written in a living organism's DNA, to a "phenotype," a physical attribute that was generated by that genotype. Those attributes can include the color of someone's hair, skin, or eyes; body shape (like height, foot size, the length of fingers and toes, or the shape of your nose); or specific body functions that might be inherited, like near-sightedness, high blood pressure, sickle-cell disease, or even whether cilantro tastes bitter.

To identify genotypes, researchers search for a pattern in our DNA that is uniquely shared (or absent) in a set of people who share a physical attribute. This is a pretty crude process; DNA is sort of like a computer program, but we understand very little of the language the program is written in. So for the most part, the best we can do is look for patterns in the DNA that correspond to physical things we can observe. These patterns are strongest when we can see that they are passed on through generations of descendants; for example, red hair. They are less valuable, but can still be important, if they are found in population groups, especially if we know the group has been genetically isolated for long periods of time, such as some Indigenous tribes; religious communities, such as the Amish; or even geographically isolated nations, such as Iceland.

This weekend's read is a new report from the National Academy of Sciences that suggests that many of the population groups commonly used today in genetic research — such as race/ethnicity, nationality, and geography — are too vague or genetically varied to be of much use and should be used sparingly, if at all, by the field. They point out that many of the terms have sociopolitical origins, rather than genetic ones, and tend to serve as proxies for cultural beliefs and practices, or shared environments, without direct measurements of those environmental factors.

Over the years, the research community has come to a much deeper understanding of the effect of the environment on how our genetics operate, a discipline called "epigenetics" that details how environmental influences can turn on and off specific genes. The report makes clear that both genetics and epigenetics are important fields that should continue to develop. But it argues that their over-reliance on population descriptors to represent environmental conditions (perhaps regional or cultural changes in diet and medicinal practices, or using geographic and national borders to represent differences in climate, altitude, and ecosystem), instead of the conditions themselves, is doing a disservice to the fields and to the populations they intend to research and serve. In truth, human genotypes are neither fully isolated, nor are they randomly distributed across the planet. It's really the worst of both worlds: There are loose associations between genotypes and race, ethnicity, geography, religion, and other population descriptors, adding just enough noise to the data such that you can neither focus on just one population nor ignore population boundaries entirely without running the risk of either over-sampling or under-sampling people with a specific genetic trait.

On the other hand, there are plenty of examples throughout history of (poorly understood) genetics being wrongly used to assert genetic superiority and justify racism, antisemitism, so-called "ethnic cleansing," eugenics, and genocide. This happened, and continues to happen, despite the fact that there is no genetic definition of "white" — or Black, or Jewish, or any of the other populations that have been systematically oppressed over time.

Now, let's be clear about what this report is not saying: It is not saying that race and ethnicity don't matter, nor that we should stop using those terms entirely. Just the opposite, in fact: It argues that race and ethnicity do matter. But for the purposes of most genetic research, they are too vague and imprecise to serve as a useful proxy for either a shared set of DNA or specific environmental factors that might cause epigenetic responses.

The report breaks out seven different types of genetic research, including gene discovery for specific human traits (such as eye color); prediction for the risk or incidence of disease or health outcomes; the study of health disparities; and the study of evolutionary history. The report recommends that race be used only as part of studying health disparities, and even then, only as a proxy for environmental effects and not genetic differences. It suggests that ethnicity/indigeneity, geography, and genetic ancestry might be used, carefully, as environmental proxies in some other types of genetic research; but that direct measurements of genetic similarity (i.e., "this set of people who all share these same genes") are the preferred method of describing populations for the purposes of most genetic research. Additionally, it emphasizes that we shouldn't assume population groups (and labels) are genetically homogeneous, distinct, have a hierarchy, or are stable over time.

Importantly, the report recommends that genetic researchers engage with the communities they wish to research to integrate their perspectives on the proper definition and usage of labels to describe them.

However, as with all systems that have been in place for a long time, making a switch such as this will face some obstacles. One such obstacle will be the federal government itself, which currently requires that federally funded medical research identify the population groups that are being studied using the very labels the National Academy report wishes to phase out, such as race and ethnicity.

This is an interesting and thoughtful report from the National Academy of Sciences, a group of many of the most highly respected scientists in the United States. It's a great example of why we have a National Academy: to address difficult issues and provide carefully considered, nuanced guidance on the best way to move forward. Changing the way research is done is never easy, nor is changing vocabulary, and it will be interesting to see how quickly the genetic research community responds to this call for a large-scale modification in how we describe populations.

Using Population Descriptors in Genetics and Genomics Research: A New Framework for an Evolving Field

Featured Image: An image of a human helix DNA structure. In this week's Weekend Reads, Kevin Schofield explores a new report from the National Academy of Sciences that suggests some widespread assumptions about genetic research are too vague, and should be used sparingly, if at all. (Image: Billion Photos/Shutterstock.com)