Joseph Graves | The Genetics of Race (Part 2)

Graves:

As a Christian, I always have hope. That’s one of my…that’s part of my faith, but, you know…and this is an opportunity by the way, because as much as I think my profession is important in terms of being able to ameliorate some of the impacts of institutional racism, I actually think the church has far more capacity to do so.

Dr. Joseph Louis Graves Jr. Professor of biological sciences at the department of nanoengineering, uh, which is part of the joint school of nano sciences and nano engineering at North Carolina, A&T state university and UNC Greensboro.

Stump: 

Welcome to Language of God. I’m Jim Stump. This episode is part two of our conversation with Dr Joseph Graves about the genetics of race and in this episode we jump right into the science. 

If you didn’t hear part one, you might want to go back and hear the story of how Dr. Graves got to where he is today, because it gives some good context and real world stories for the scientific conversation that follows. 

The mainstream belief, at least within evolutionary science is that there is no genetic basis for race. But as you’ll hear in this first part, that belief isn’t necessarily widely held within all of biology. That’s where we start the episode. And I’ll warn our less scientifically inclined listeners that it does get a little complicated at times as I try to probe and understand some of these nuances myself. But stick with us because there’s some great conversation that follows. If you need a refresher on some basic principles of evolution alongside this we’ve got some links in our shownotes to some great resources for all kinds of audiences at the BioLogos website. 

At the end of the episode Dr Graves gives a powerful message to the church and it is one we at BioLogos are doing our best to hear and take to heart, and we hope you will do the same. 

Let’s get to the second half of the conversation.

Stump:

Okay. So let’s get to racism more properly here. The standard claim, the orthodoxy in your field, as I understand it, is there is no biological or genetic basis for identifying races among Homo sapiens today. Can you unpack that for us? What is it that scientists mean by that? I mean, I assume we have to have some sort of working definition of what race is, and then we collect data to see whether it bears that out. Is that how this works?

Graves:

Okay. So I would first say, Ok Jim, that’s the modern orthodoxy. And that’s probably the orthodoxy amongst population and evolutionary geneticists, but not necessarily all of the other subdisciplines of biology. Now there have been surveys taken over the last 20 years where biologists are asked do humans—and here that we mean anatomically modern humans—do they have biological races? And the results of those surveys indicate that not everybody agrees with this modern orthodoxy and that there are significant pools of scholars who disagree with that modern orthodoxy. But when I’ve examined the views of these individuals in groups, the first thing that I find lacking is a definition of what they mean by a biological race. And so I utilize the definitions that are used in my discipline, evolutionary biology, and there are basically two portions of that definition. The first has to do with the amount of genetic variation that exists within subgroups in that species versus the entire species.

Stump:

So explain that to us.

Graves:

That definition looks at the genetic variance found in the subpopulation. So if we take humans, we could take the continents as a basis of judgment. So we could take sub Saharan Africa or Africa, we could take Europe, we could take Eurasia, we could take East Asia, we could take Australia, we can take the Pacific islands, we can take the Americas.

Stump:

So that’s what you mean by a sub population?

Graves:

Sub population. Yeah. Now of course, everyone who has any sophistication in population genetics knows that populations themselves are somewhat arbitrarily defined. But if we want to counterpose the evolutionary view of human biological variation with the essentialist one, we’re really talking about looking at these continents. And so when we look at the continents and we measure the number of genetic variants that are found across the human genome—and just so we’re talking about 3.3 billion base pairs. And 99.9% of those are the same in all people. But that 0.1% is not an insignificant number when you’re talking about 3.3 billion base pairs. So that’s around 300 million and that’s certainly enough to produce the variation that we see amongst individuals and also groups of individuals. But when we look at that polymorphic variation and we ask what is the likelihood that we find a particular genetic variant in a given population alone, versus cosmopolitan distribution in which it’s found in all world populations, about 85% of those variants are found in all world populations. And then about 10% of them are found distributed between continents and then about 5% refers to variation within continents. So when we look at this overall genetic variation between groups and within them, there’s much more genetic variation within them than there is between them.

Stump:

So let me see if I understand you here. When you say the cosmopolitan variation, so you’re saying among these places on our genome, where there is variation, that 0.1%, the vast, vast majority, 85% of those variations you’d find similar variations from all of these different subpopulations, rather than this one continent, people of ancestry from there, have this one and people from another continent at that same place in the genome have something different. Most of the variation is spread across the entire human race. That’s what you’re saying?

Graves:

Yeah. And also just to be a little bit more sophisticated now, the frequency or the occurrence of those variants may not be the same in all places, but they’re found everywhere.

Stump:

So what would some of those genes be for, that you’re talking about in this regard, or is that too simplistic of a notion?

Graves:

No. I mean, that’s not a simplistic notion at all. I mean, there are certainly genes that are associated with geographic variation, but they’re not associated in the way people would think. So, for example, if we look at people who live in rainforests, there are genetic variants that are associated with survival and successful reproduction in rainforests. Now, if you’re of the mind that well there are only one place in the world where there are rainforest and that’s Subsaharan Africa, you would be wrong, right? There are rainforests all over the world. And so these rainforest phenotypes, which occurred from selection for rainforest traits are the same in the Brazilian jungles as they are in African jungles. And so you need to think differently about what geography is. If you think geography is just a shape on a map then you’ve got it wrong.

Another example is altitude. There are high altitude adapted populations all over the world, in the Himalayas, in the East African rift plateau, in the Andes plateau. And again, these people differ in other genetic traits, but they share similar adaptations to high altitude. So you need to look at geography differently to be able to understand how you can have genetic variants, which are found everywhere, but then you can have specific variants that are found for specific adaptation to different conditions, such as malaria. Anti-malarial adaptations occur where malaria is found. And it’s found in the tropics of Africa, in Brazil, in the Mediterranean, in fact, the Greeks had to move their city states away from the coast because malaria was killing too many people. And so the sickle cell variant is found in Greeks, just as well as it’s found in Nigerians, but it’s not found at any appreciable frequency in high altitude living Kenyans or in native South Africans where malaria transmission isn’t occurring at high frequency.

Stump:

So then one of the obvious ways socially that race comes into discussion here is with skin color. What do we know about the genetics of skin color and how that is distributed around these different populations?

Graves:

Well, there’s a very famous anthropological map called Biasutti skin color map in which you can see the distribution of skin colors around the world. And no one will be surprised when I say this, is that people in tropical regions tend to have darker skin than people who live in temperate regions and people who live in Arctic regions. Now, this adaptation of dark skin, by the way, is an evolved one because our ancestors, who we talked about early in the show, 6 million years ago, still had hair. And since they had dark hair, their skin was light, but when humans lost their hair and their skin was exposed to intense sunlight, darker skin evolved in the tropics and all tropical people retain that dark skin. Then as people began to migrate into the temperate zones, they began to lose skin pigmentation because it is a detriment with regard to vitamin D synthesis in lower sunlight intensity.

But one of the things we know is that this was a gradual process. For example, there was a study of an ancient fossil found in Spain. And this individual whose death was dated to be about 8,000 to 10,000 years ago. And they examined the genes which are associated with dark pigmentation and found that this person living in Spain had still had dark skin. So they hadn’t evolved the lighter skin that you see in modern Spaniards yet. So this is a process that occurred over time. And eventually we ended up with differentiation in skin color, but that’s associated with latitude, okay? And solar intensity.

Not with these subpopulations of which continent your ancestry is from? Is that what you mean?

Graves:

Right, so for example, Sri Lankans by 19th century anthropological classification would be called Caucasians, but they have extremely dark skin. Their skin is as dark as anybody in Subsaharan Africa.

Stump: 

So it was just based on geography?

Graves:

It’s based upon geography, specifically the aspect of solar intensity at that latitude.

Stump:

You’re not saying that there couldn’t ever be races, right? There could have been races within our species. If there had been more say reproductive isolation in these groups over time, it’s just that’s not what we find today is that the…

Graves:

Well, let’s go back to this ancient DNA question. So one of the disagreements I have with David Reich is whether ancient DNA is really telling us that there was so much local adaptation between human groups, that they were in fact, biological races. I don’t think that the evidence supports that at all. So what we had was human beings spending most of their time in sub Saharan Africa, 200,000 years, and then climatic conditions change, people begin to leave and migrate around the world at around a hundred thousand years ago. But these groups always had sufficient migration between them. And if you remember our basic mechanisms of evolution, the thing that retards the formation of new species is migration and reproduction between groups. So with anatomically modern humans there were always sufficient migration between groups such that genes flowed back and forth between them.

So there might be some local adaptation to a place, but then those populations would then…either whatever isolation was there broke down and new individuals came in contact. And so gene flow between modern humans throughout our entire history has always been much, much greater than isolation. And so therefore we never evolved geographical races. Now, could that happen in the future? If the world continues the way it is now, the answer would be no way because we are a cosmopolitan in the sense that people can get on a flight today—but maybe not today because of COVID, but that’s also why COVID got to the United States—because you can get on flight today in Washington, DC and be in Beijing in less than 12 hours. My wife was born in Seoul, South Korea. I was born in Westfield, New Jersey. Before the modern world, the chances of us meeting each other were probably zero.

Stump:

So but throughout history there was enough of that kind of…is there any kind of estimate on how much of the intermingling of those semi-isolated populations there would have to be in order to prevent significant enough differences to accrue over time?

Graves:

Yes, in fact, and again, without exact numbers in front of me, if you use Sewall Wright’s Island model of Migration, as I remember the numbers, it only took about one person moving between major population centers every thousand years to maintain enough gene flow to prevent the formation of strong genetic variation. Now you can check my numbers. Because again, I don’t have those exact numbers in front of me, but it takes a very small amount of migration to maintain essential genetic unity between subgroups to prevent the formation of geographical races. And going forward, if the world continues to operate the way it does now, that’s never going to happen. Now, if we have a catastrophic collapse of civilization and human beings survive in isolated pockets, then maybe biological races could form.

Stump:

Or we send a colony to Mars or Alpha Centauri or something.

Graves:

Yeah. Something like that would absolutely lead to the formation, eventually over time. If you send a spaceship to Alpha Centauri, and then two planets break down with regard to communication, the people on Alpha Centauri would eventually become a different race from the people on earth. Sure.

[musical interlude]

BioLogos:

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Stump:

Okay. So let me try to channel one of the, I think intuitive or gut level response some people have about this, which is a version of “okay, but come on, isn’t it just obvious that there are some racial differences and characteristics, just look at the NBA and the NFL, which are predominantly African American, right.” What’s wrong with that kind of thinking?

Graves:

I have written a number of responses, detailed scholarly responses to that claim.

Stump:

That’s why I’m asking you.

Graves:

And I know you know that. I’m just going to say that for your listeners. Now, one of the chapters of my second book, The Race Myth was on the number of persons of European descent in the NBA. And the fact that persons that are called black have African descent and European descent. So when you, at that time, when you compare the number of Subsaharan Africans in the NBA with the number of Europeans in the NBA, there were far more Europeans in the NBA than there were sub Saharan Africans. So if we were going to go on the basis of a sort of pure racial model, then you’d say the genes for basketball playing ability came from Europeans, not from Africans. But nobody thinks of it that way.

Now, at the end of the day, what we know about sports and the number of individuals from different ethnic groups in those sports, it’s strongly related to the culture that those individuals came from. Even modern basketball, for example, didn’t become an African American sport until the urban renewal of the 1960s in which communities of African Americans were isolated from, in some ways in the inner city, from the rest of the communities in the suburbs. And basketball became a relatively cheap and inexpensive way for kids to entertain themselves. And so I remember my neighborhood, if you couldn’t play basketball, you really couldn’t come out of the house. And so every Saturday and every Sunday we would go over to the court at the elementary school, rain, snow, didn’t matter, would shovel off the court and we’d play basketball all day long, cause we didn’t really have much else to do.

So in the same vein, if you take a sport like volleyball, and I’m actually somebody who played both sports at a very high level. So I played volleyball at the University of Michigan and I also play basketball. And I can tell you that, at least in my own personal experience, you have to be a better athlete to be a volleyball player then a basketball player. But if you look at the USA Men’s Volleyball team, the vast majority of people are from orange County in Southern California, and there are people of European descent. You look at the Men’s Basketball team, a vast majority of people of African descent from all over the United States, but athletically, the two things require the same set of capacities.

Stump:

Another example of that might be in hundred meter sprints at the Olympics, where you see these dominated by United States and Jamaica, where the claim is often people of West African ancestry. Well, none of the countries in West Africa have won any medals in any of the sprints, right? So there must be some strongly social component to bringing out those abilities, at least. Right?

Graves:

And not only that, I actually looked at the times of people from…and here’s something that people really, I hope will nail this in a coffin, but when you look at the times of the previous heats, not the finals, but you look at the times of the previous heats, there’s milliseconds difference between European runners who didn’t make the finals and West African descended runners who did. When you look at female athletes in those same events, you don’t see a domination of people of Western African descent at all. So if this were really the genetics of race playing a role in determining who’s the world leaders in these sprinting events, then you would see it in both genders. And you don’t see that.

Stump:

To explain this further than, even the genetic difference within a population, as opposed to across populations, we can describe this way too, would it be accurate then to say that maybe there are, within people of African descent, some teeny bit higher proportion of whatever the genes are that make you fast at the a hundred meter sprints, but there are also a lot of people of African descent who are pretty slow at those. And so there’s an enormous variation within that subpopulation. There’s more variation within that sub-population then there is average times in the hundred meter sprints across those populations. Is that fair to say, or am I mixing this up again?

Graves:

No, no, you’re not. I mean, it is fair to say that, but I’ve also looked at what we would expect when we looked at the size of the population, say people of European descent in the United States and people of African descent in the United States, if we look at the size of those populations and we look at the extreme right end in terms of athletic ability, there should be far more persons of European descent of world-class athletic ability than there are persons of African descent of world-class athletic ability, simply just due to the difference in population size. So we also, by the way, see that. But people don’t see it because of the sports that they examine. So this is implicit bias in terms of it will, if you happen to watch basketball and football, you come to the impression that all these great African descended athletes are in these two sports. But what if you look at, for example, European football in which you see all of these great athletes of European descent dominating football, worldwide, and fewer people of African decent dominating football. And then swimming, for example. Same muscle groups that are involved in sprinting are involved in swimming. And the narratives, of course, in the Olympics in which Usain Bolt and Michael Phelps were both at their prime, you heard a narrative about genetics of sprinting with regard to Jamaican sprinters, but you never heard genetics of swimming argument with Michael Phelps.

Stump:

Okay. So no biological or genetic basis for identifying races among Homo sapiens today. And yet there’s some genetic structure to people groups or identifiable—I think the word that sometimes is used is clusters—genetically. How does that work? And what’s the relationship of that to what we usually mean by race?

Graves:

So the first thing one has to address is the meaning and the method by which these clusters are produced. Now, there’s an algorithm called STRUCTURE and it’s designed to cluster a population or individuals with supposed ancestry. Now it starts with an assumption and underlying assumption that most people don’t understand, which is, it starts with the assumption that there were once racially separated populations within that species. So in humans, it would…it starts with the assumption that there once was an African race, there once was a European race, there once was an East Asian race, there once was an Amer-Indian race. But the reality is, is that that never existed. And so what it does, is it uses modern, allele frequencies, or modern gene frequencies to impute ancient gene frequencies. So the reasoning behind STRUCTURE is actually circular. It’s assuming an ancient differentiation that didn’t exist using modern differentiation.

So that’s my first concern with the STRUCTURE algorithms. Now, if we then say, let’s apply these as people have done to modern humans, well these algorithms identify genetic variation, which is associated with continents, such as Africa, Eurasia, East Asia, and so on. And they then compute how many of the genes in an individual came from those various areas. And then they cluster them all together to give you your clusters. Now this still shows continuous variation across the human species and the number of clusters you get depends upon the number of genetic markers you use, the number of people that you survey and where they came from. So if you’re only taking samples from Subsaharan Africa, Eurasia, East Asia, the Pacific and the Americas, you can get this appearance that there’s this clustering of human beings. But if you were taking more geographically close samples of human beings, you would reconstruct the continuous variation that we have argued for over the last, going back to the 40 years.

Yeah. So I’m not a big fan of clustering algorithms. And they certainly don’t reconstruct the notion that there are these geographically defined races. It is really a question of what the algorithm was designed to do and how the sampling was taken to give the results that are displayed in various analyses.

Stump:

So I took one of those consumer DNA test kit things. What’s that really doing then? Mine comes back pretty boring. I’m about half from England and half from Germany with teeny little bit of Ireland and Eastern Europe. But what does that really mean? Because how far back are we going? We already talked about the fact that we all came from Africa, not that long ago. So are they trying to identify these clusters you were just talking about, and it’s really not telling us what we think it’s telling?

Graves:

Well it’s clear that these ancestry DNA tests are not telling us something about our deep ancestry. They are based on the clustering algorithm idea and for persons of European descent, for example, or East Asian descent or regions of the world where there have not been a tremendous amount of population demography shifts over the last 400 years, they’re probably reasonably accurate estimates of ancestry. So if all of your ancestors came from Central China, and that population has been there for the last 400 years without major demographic shifts, probably an accurate estimation of your ancestry from Central China. For persons of African descent, this is far more problematic because there have been major demographic changes, particularly in the regions of Africa that were the subject of the transatlantic slave trade. So populations migrated that were decimated by wars. So sampling some population that happens to live in Sierra Leone today isn’t necessarily the group that lived there 400 years ago.

So if a person’s DNA test says, well, you know, you’re from this region of West Africa, can’t really be sure that that’s where your ancestors came from. And so there are real issues with regard to trying to, again, impute ancient or past populations from modern samples of those same regions, particularly in places where there’s been population demographic shifts, a great scale.

Stump:

And what about the medical risks that are identified by these kinds of tests? Did it used to be thought that that tracked more closely with race? And now we just have a more fine grained analysis that these are individual as we get closer and closer to individualized medicine and each of us has our genome sequence that will know those medical risks. The generalizations by race are no longer helpful or valid?

Graves:

Certainly by, again, what I call socially defined race, they’re completely invalid. So it comes down to the degree to which a risk factor associates with ancestry. So there are particular diseases that are associated with West African ancestry. And so for example, there’s a gene that once conferred, or confers resistance to a trypanosomes infection, which also in the Western environment, meaning the environment of the United States, raises the risk of kidney disease. But the important thing to understand here is two fold. One, it is an individual variant, which you may or may not carry, and, you know, all people of African descent don’t carry this variant. For example, I carry a G6PD deficiency, which is am anti-malarial adaptation, which I inherited through my mom. But my dad didn’t have it. So… Then the other side, of course, is understanding that this variant is not a racial variant in that it’s a variant associated with a specific environmental adaptation. So this notion that we’re going to eventually get to personalized medicine, I think is, might be a little bit far off than people think. But it’s important to recognize that ancestry does tell you something about your disease predispositions. But the important thing to understand is that this is completely contingent upon the environment in which an individual’s living. So for example, a lot of the variants which have been associated with high blood pressure or hypertension risk amongst people of African descent living in the United States have absolutely no association with it for people living in West Africa, right? So it is environment and gene. There is no context in which the gene is not influenced by the environment in which it’s living in.

Stump:

Okay. Finally, if I may here still, there is a social reality of race. I’m curious how a scientist like yourself who understands so well the genetic arguments, who in fact has developed many of these genetic arguments, that there are no biological races, how do you react though when you see the evening news these days of the very real racial tensions, systematic racism in our country, that you yourself have worked to a try to help eliminate? What’s the social reality of race from your perspective?

Graves:

Along with Eric Jarvis, I just wrote a commentary on racial discrimination in the enterprise of science that came out in The Scientist on Friday. Throughout my career, and we talked about this earlier in the show, there were impediments that were placed in my way that had to do with my membership in a racially subordinated population in the United States. And that’s real and that still exists. And of course because I am a university professor, things aren’t quite as bad for me as people who are chronically unemployed or underemployed in the society. But the same risks with regard to things like being arbitrarily arrested or killed, because of my socially defined race are real for people, even in my social status. For example, there was a professional tennis player who was gang tangled by the New York police last year. So at the end of the day, institutional racism means that racism and racial ideology is part of every institutional structure in the United States. And it hasn’t gone away. As much as people are trying to paint a narrative that we live in a post racial society, particularly because of the election of Barack Obama a few years ago, that just is simply not true. During his administration, we saw an uptick of the number of police killings of unarmed African American youth. We saw, and it continues, an increase in the number of African Americans incarcerated during his administration. The unemployment numbers for African Americans didn’t come down during his administration. So while, you know, we’ve had some moments of clarity and progress over the last couple of decades, we are still a long way away from removing and ameliorating the impact of institutional racism on racially subordinated minorities in this country.

Stump:

Is this moment here, that I suppose is defined by the death, by the murder, of George Floyd, is this moment any different than the others, do you think? Is anything changing?

Graves:

I can tell you one thing, I have been writing, as you know, about racial ideology in biology for going on 30 years. The murder of George Floyd has finally gotten a lot of people in my field to start reading my articles. I’ve been getting tweets from all over the place like, “Oh, we finally read your article. It was fantastic.” Or, you know, and “we didn’t know this stuff.” And I’m like, well, why didn’t you know this stuff? Because I wrote that article, you know, 20 years ago.

Stump:

Do you see any signs of hope in this current moment that makes you think this is any different?

Graves:

Number one, as a Christian, I always have hope. That’s one of my…that’s part of my faith. But, you know, and this is an opportunity by the way, because as much as I think my profession is important in terms of being able to ameliorate some of the impacts of institutional racism, I actually think the church has far more capacity to do so. And so I spent time the last couple of years being part of the racial justice and reconciliation commission on the Episcopal church of North Carolina and working with my own local church in this regard, but there is far more the church can do. And here I mean, the white church, can do to dismantle institutional racism than any institution within this country. And we argue in my denomination that this is what we’re called to do. This is what we should have been doing for a long time. And so if this moment has awakened people of good faith, and here, again, I’m speaking to other Christians, if this moment has not convinced you that the church needs to take action, that individual Christians need to take action against this injustice. I don’t know what can, other than, you know, Jesus popping down in the middle of Washington D.C. and saying, all right, it’s this all over it’s time for the rapture.

Stump:

Well, Dr. Graves, thanks so much for talking to me. I hope we can talk again to you some time and that the realities you described scientifically will be more apparent in our broken and fallen world than they are right now. So thank you for your work and thank you for talking to me today.

Graves:

Thank you, Jim, for having me on this podcast.

BioLogos:

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