The science of racism: Genetics

Marissa Lithopoulos
4 August 2015

Above: Image ©

This is the first in a series of four articles that will explore racism from the perspectives of genetics, evolution, biology, and psychology.

I am a first-generation Canadian, the daughter of Greek and Indo-Guyanese immigrants. Although I was born and raised in Canada, my ethnicity did create certain challenges growing up. We lived in a largely “white”, multi-generational, suburban neighbourhood. When my classmates told stories about their weekend hockey tournament, I would tell them about the wonderful music at my cousins’ puja. Or the delicious lamb I enjoyed during a Greek Orthodox Easter celebration.

Did you know? Only 5-15% of genetic differences within the human genome occur between populations, which are often referred to as races. By contrast, 85-95% of genetic differences occur within individual populations. I have not been the victim of blatant racism, but I do occasionally encounter prejudice. People tend to assume that there is a connection between how you look, how you act, and who you are. Ironically, because I look Greek and have no typical Guyanese features, people often comment that my skin should be darker. My mother comes from a place that is very mysterious to my hometown neighbours. Many of them admit that they have never even heard of Guyana. They seem to expect me to have a more exotic (to a white Canadian) appearance as well.

Before going further, it is important to define race, ethnicity, and genetic population—three words often used interchangeably. A race is a group of people who share a similar physical appearance that is associated with a specific geographic area. Ethnicity is a more complex term. It categorizes people who not only look alike, but also have similar behaviours and cultural practices. Lastly, a genetic population is a group of people with a high degree of genetic uniformity. Often, these genetic similarities also reflect a shared culture or geographic origin.

People’s assumptions about my appearance and my ethnic heritage are very relevant to what geneticists have discovered about race. To understand what I mean, you have to distinguish between phenotype and genotype. A phenotype refers to the visual, observable characteristics of a living thing. By contrast, a genotype is an organism’s genetic makeup. For example, Stan and Frank might look very different from each other. They would normally be considered to belong to different races. Many people would therefore assume that they have very different genetics.

Did you know? Scientists have found no credible genetic evidence to support the categorization of people into races. In fact, despite having very different phenotypes, Stan and Frank could very well have very similar genotypes. Researchers have found that there is more genetic variability and diversity within individual races than between different races. For example, one study looked at 109 DNA markers to analyze the genetic differences between 16 different human populations around the world. It found that a lot of the genetic diversity that exists on a global scale is reflected in small populations from very specific geographic areas, such as the Mbuti pygmies of Zaire. On the other hand, there are very small genetic differences between Northern European and Chinese populations—people who look quite different and live far apart!

So remember: big differences in phenotype do not necessarily mean big differences in genotype. Yet people still tend believe that phenotypic diversity (whether people look the same) reflects genetic diversity. And this belief promotes classifications and implicit biases based on race. Implicit biases are a type of unconscious judgement or behaviour. For example, you might prefer to spend time with people from your own race and you might treat certain people unfairly based on their appearance and ethnicity. And you might not even be aware you’re doing it.

So if the idea of race isn’t based on genetics, where does it come from and why is it so powerful? And why are so many other people’s implicit biases based on how you look, when they so often have very little to do with who you are, let alone your genetics? Research in the fields of biology, evolutionary science, and psychology provide some answers to these important questions. And this research will be the focus on my next articles on the science of racism.

Learn more!

Magazine article on why society, and not your DNA, determines your race:

Why Your Race Isn’t Genetic (2014)
Michael White, Pacific Standard

Scientific articles on human genetic diversity and the relationship between genotype and phenotype:

Implications of the apportionment of human genetic diversity for the apportionment of human phenotypic diversity (2015)
M. D. Edge & N. A. Rosenberg NA, Studies in History and Philosophy of Biological and Biomedical Sciences 52
Link to abstract. Registration or subscription required to view full text.

Population genetics models of local ancestry (2012)
Simon Gravel, Genetics 191

Worldwide human relationships inferred from genome-wide patterns of variation (2008)
J. Z. Li et al., Science 319
Link to abstract. Registration or subscription required to view full text.

Race: a genetic melting-pot (2003)
M. W. Feldman, R. C. Lewontin & M. C. King, Nature 424
Registration or subscription required to view full text.

Informativeness of genetic markers for inference of ancestry (2003)
N. A. Rosenberg, L. M. Li, R. Ward & J. K. Pritchard, American Journal of Human Genetics 73

Genetic structure of human populations (2002)
N. A. Rosenberg et al., Science 298
Link to abstract. Registration or subscription required to view full text.

An apportionment of human DNA diversity (1997)
G. Barbujani, A. Magagni, E. Minch & L. L. Cavalli-Sforza, Proceedings of the National Academy of Sciences 94

Does Race Matter? (1995)
Pierre L. Van Den Berghe, Nations and Nationalism 1

Marissa Lithopoulos

I was born and raised in Ottawa and am a proud University of Ottawa student. I completed my undergraduate studies with an Honours degree in Biomedical Science and a Minor in Philosophy. I am now a PhD Candidate in Cellular and Molecular Medicine. I enjoy travelling, rhythmic gymnastics, and playing the guitar. I joined Let’s Talk Science as an outreach volunteer in 2014 and have absolutely loved it! I think science is wonderful because it allows us to ask (and sometimes answer) deep questions about our universe.

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Avatar  Katiestrach

This is quite interesting from a scientific point of view! A good read!