What is the current thinking about race and genotype?
April 11, 2017 6:54 AM Subscribe
I have heard informally that the Human Genome Project has changed how scientists are thinking about race. Are there any great articles or documentaries that explain the current thinking about race and genotype? Or, if you are a scientist or someone otherwise well-versed, could you explain it to us? I am interested in both understanding the science, as well as how it is changing how we think about society.
I found one interesting report with an an evocative quote in it that gestures at the debates I am trying to wrap my head around. It is:
"The last great battle over racism will be fought not over access to a lunch counter, or a hotel room, or the right to vote, or even the right to occupy the White House: It will be fought in the laboratory, in a test tube, under a microscope, in our genome, on the battlefield of our DNA." (Henry Louis Gates Jr, cited in Anthony 2008:36)
I found one interesting report with an an evocative quote in it that gestures at the debates I am trying to wrap my head around. It is:
"The last great battle over racism will be fought not over access to a lunch counter, or a hotel room, or the right to vote, or even the right to occupy the White House: It will be fought in the laboratory, in a test tube, under a microscope, in our genome, on the battlefield of our DNA." (Henry Louis Gates Jr, cited in Anthony 2008:36)
Best answer: I'm a genomicist, and I don't really think in terms of races when it comes to genomes, I think in terms of populations, and the frequencies of particular variants within them.
There are differences between groups of people because base changes in the genome (and thus, traits) that spontaneously appear in one population often are not seen in other populations. You can probably think of lots of physical manifestations of this (eye color, curly hair, skin color). More importantly to me, there are important medical implications - different variants make different groups of people more or less susceptible to particular diseases. Another application is in pharmacogenomics, which is based on the fact that people with slight differences in key genes may respond to drugs in very different ways. (One person might metabolize a drug faster, for example, and thus need a higher or more frequent dose).
Since people have traditionally tended to procreate with people in their immediate geographic area, populations are isolated from each other, and variants may be more or less common in different groups. This, these traits often happen to fall along traditional racial lines. This is not always the case, however. For example, in Finland, very small groups of people were sent to settle the far north hundreds of years ago. This created a "bottleneck" that resulted in significant inbreeding, and previously rare variants became common in these populations. As a result, these populations have different rates of some diseases than the rest of Finland. From an appearance or even cultural perspective, these people are Finnish, but their genomes have unique features. (some of which make it easier to find medically-relevant genomic variants that can help with identifying key genes, drug design, etc).
Does this get at some of what you're talking about?
posted by chrisamiller at 7:26 AM on April 11, 2017 [20 favorites]
There are differences between groups of people because base changes in the genome (and thus, traits) that spontaneously appear in one population often are not seen in other populations. You can probably think of lots of physical manifestations of this (eye color, curly hair, skin color). More importantly to me, there are important medical implications - different variants make different groups of people more or less susceptible to particular diseases. Another application is in pharmacogenomics, which is based on the fact that people with slight differences in key genes may respond to drugs in very different ways. (One person might metabolize a drug faster, for example, and thus need a higher or more frequent dose).
Since people have traditionally tended to procreate with people in their immediate geographic area, populations are isolated from each other, and variants may be more or less common in different groups. This, these traits often happen to fall along traditional racial lines. This is not always the case, however. For example, in Finland, very small groups of people were sent to settle the far north hundreds of years ago. This created a "bottleneck" that resulted in significant inbreeding, and previously rare variants became common in these populations. As a result, these populations have different rates of some diseases than the rest of Finland. From an appearance or even cultural perspective, these people are Finnish, but their genomes have unique features. (some of which make it easier to find medically-relevant genomic variants that can help with identifying key genes, drug design, etc).
Does this get at some of what you're talking about?
posted by chrisamiller at 7:26 AM on April 11, 2017 [20 favorites]
Response by poster: Hi again. These responses are great, and they are getting at what I am trying to figure out.
On a related note, I recall someone saying about 10 years ago that the Human Genome Project had determined that there were new large groups of people that are kind of like races, but which did not exactly overlap with the old ideas of race. I think that I heard there were about 20 of those groups. Is that true? If so, do any of you know who has argued that, and whether it is considered respected science today?
posted by mortaddams at 7:45 AM on April 11, 2017
On a related note, I recall someone saying about 10 years ago that the Human Genome Project had determined that there were new large groups of people that are kind of like races, but which did not exactly overlap with the old ideas of race. I think that I heard there were about 20 of those groups. Is that true? If so, do any of you know who has argued that, and whether it is considered respected science today?
posted by mortaddams at 7:45 AM on April 11, 2017
Best answer: Sarah Tishkoff is a prominent researcher on the genetics of human populations and a professor at Penn, who frequently writes on this subject. You might check out her recent interview with NPR, "Is It Time To Stop Using Race In Medical Research?" or her media appearances more generally.
posted by grouse at 7:46 AM on April 11, 2017 [4 favorites]
posted by grouse at 7:46 AM on April 11, 2017 [4 favorites]
Best answer: I think that I heard there were about 20 of those groups
You're thinking of haplotypes, and the number of them changes depending on the definitions used. They're very much real, established science, and they're useful in a variety of discussions, probably most popularly in relating individuals living today back to prehistoric human subpopulations across time and geography (i.e. finding out where your ancestors came from). Have you read The Seven Daughters of Eve? This explains one way of looking at these groups. It's also relevant to things like the National Geographic Genographic Project and other similar programs.
I work in toxicology, and toxicogenomics (how people with different heredities react, similarly or differently, to drugs and chemicals) is very much a hot field, though it has a long way to go. The word "race" is a very loaded one, and we don't use it much, but we're talking about the same thing in a sense.
I'll poke around for some informative articles and share them later today.
posted by late afternoon dreaming hotel at 7:56 AM on April 11, 2017 [2 favorites]
You're thinking of haplotypes, and the number of them changes depending on the definitions used. They're very much real, established science, and they're useful in a variety of discussions, probably most popularly in relating individuals living today back to prehistoric human subpopulations across time and geography (i.e. finding out where your ancestors came from). Have you read The Seven Daughters of Eve? This explains one way of looking at these groups. It's also relevant to things like the National Geographic Genographic Project and other similar programs.
I work in toxicology, and toxicogenomics (how people with different heredities react, similarly or differently, to drugs and chemicals) is very much a hot field, though it has a long way to go. The word "race" is a very loaded one, and we don't use it much, but we're talking about the same thing in a sense.
I'll poke around for some informative articles and share them later today.
posted by late afternoon dreaming hotel at 7:56 AM on April 11, 2017 [2 favorites]
Best answer: Mol bio grad student checking in. I do not work with humans.
In general, for most of human history, groups of people have been isolated. Some are more than others, due to geographical or social factors - for example, Ashkenazi Jews. You're going to find concentrations of some alleles in some populations and not others.
People also tend to mate with people who are similar to them to an extent in appearance and also in personality and also background (although with a different major histocompatibility complex), which means by and large 'interracial' couples are less common than ones that aren't. People also tend to mate with the people around them.
Race, though, is a social construct because it lines up so *poorly* with scientific information and is based on a superficial visual evaluation along with social signals. There is more genetic diversity in Africa than outside it, a wackily diverse group of peoples are considered 'white' (and some used not to be, like the Irish) and 'black' (ranging from Africans to Indigenous Australians, and these groups of people are distant genetically) and pretty much everything else (East Asians and Indigenous Americans share a lot of genetics because of the Bering Land Bridge but are considered racially different). People are also considered 'whiter' or whatever else depending on their behavior, and 'white' is considered by our racist society to be the privileged standard.
Mostly the reason race is even a thing is because our ancestors were uneducated, ignorant turds with an imperialist impulse and a tendency to dehumanize people.
posted by actionpotential at 10:37 AM on April 11, 2017 [7 favorites]
In general, for most of human history, groups of people have been isolated. Some are more than others, due to geographical or social factors - for example, Ashkenazi Jews. You're going to find concentrations of some alleles in some populations and not others.
People also tend to mate with people who are similar to them to an extent in appearance and also in personality and also background (although with a different major histocompatibility complex), which means by and large 'interracial' couples are less common than ones that aren't. People also tend to mate with the people around them.
Race, though, is a social construct because it lines up so *poorly* with scientific information and is based on a superficial visual evaluation along with social signals. There is more genetic diversity in Africa than outside it, a wackily diverse group of peoples are considered 'white' (and some used not to be, like the Irish) and 'black' (ranging from Africans to Indigenous Australians, and these groups of people are distant genetically) and pretty much everything else (East Asians and Indigenous Americans share a lot of genetics because of the Bering Land Bridge but are considered racially different). People are also considered 'whiter' or whatever else depending on their behavior, and 'white' is considered by our racist society to be the privileged standard.
Mostly the reason race is even a thing is because our ancestors were uneducated, ignorant turds with an imperialist impulse and a tendency to dehumanize people.
posted by actionpotential at 10:37 AM on April 11, 2017 [7 favorites]
Best answer: This is a great study on the topic. If you sample people like they did on the left of Figure 1, you find races. If you sample people like they did on the right, you don't find races. It should be pretty clear why.
With good sampling design - like what's on the right in Figure 1 - you find that gene frequency varies gradually with geographic distance. We form not clades, but clines.
posted by clawsoon at 11:30 AM on April 11, 2017 [2 favorites]
With good sampling design - like what's on the right in Figure 1 - you find that gene frequency varies gradually with geographic distance. We form not clades, but clines.
posted by clawsoon at 11:30 AM on April 11, 2017 [2 favorites]
Best answer: A relevant (extended, sorry) quote from the study I linked, having to do with the usefulness of racial classification for medical treatment:
The absence of strong continental clustering in the human gene pool is of practical importance. It has recently been claimed that “the greatest genetic structure that exists in the human population occurs at the racial level” (Risch et al. 2002). Our results show that this is not the case, and we see no reason to assume that “races” represent any units of relevance for understanding human genetic history. In clinical practice, the “classification” of people into “races,” as recently suggested (Risch et al. 2002; Burchard et al. 2003), could perhaps have some justification as a proxy for differences in environmental and other factors of relevance for public health or to help identify rare disease alleles (Phimister 2003). However, in the absence of other knowledge, most alleles influencing susceptibility to disease or outcome of medical interventions cannot be expected to show significantly different frequencies between “races.” An exception may be genes where different selection regimes have acted in different geographical regions. However, even in those cases, the genetic discontinuities seen are generally not “racial” or continental in nature but depend on historical and cultural factors that are more local in nature. For example, the hemoglobin S allele that causes resistance to malaria occurs not only in sub-Saharan Africa but also in southern Europe, the middle East, and India (Cavalli-Sforza et al. 1994). Lactose tolerance occurs both in Europe and in Africa (Sahi 1994), and the deleted allele of CCR5 that confers resistance to human immunodeficiency virus occurs in Europe as well as in Asia (Martinson et al. 1997). Thus, even for a rapid and rough evaluation of genetic risk factors, “racial” background is of limited use, and direct analysis of the relevant gene is the only reliable way to evaluate genetic risk in an individual (Cooper et al. 2003). Fortunately, this will become increasingly possible as the genetic components of more diseases become elucidated.posted by clawsoon at 11:44 AM on April 11, 2017 [2 favorites]
Best answer: Clustering of 770,000 genomes reveals post-colonial population structure of North America. This article isn't a general answer to your question. But it is an excellent example of the intersection of race and genetics in current scholarship.
posted by Nelson at 1:30 PM on April 11, 2017
posted by Nelson at 1:30 PM on April 11, 2017
Best answer: Gates is talking about racism, not race, which doesn't exist because humans don't have subspecies. In "the battle over racism" he's saying those technologies are going to be the ones that racists are going to use to try to prove that races are real, in service of racism (which is the perpetuation of the idea of race for sociopolitical organization).
posted by rhizome at 4:45 PM on April 11, 2017
posted by rhizome at 4:45 PM on April 11, 2017
Best answer: You're thinking of haplotypes
Not a population geneticist, but: I think you mean "haplogroups" (my understanding is that haplotypes are groups of genes inherited from a single parent, and haplogroups are clusters of similar haplotypes that share ancient polymorphisms on either the mitochondrial DNA or the Y chromosome).
Also, the fact that people can be clustered into ~20-ish haplogroups doesn't mean that this is the "true" number of ancestral populations or whatever; it's just one way of carving up the data. Depending on the question you're asking, finer- or coarser-grained groupings might be more appropriate. In general, clustering is a fraught statistical (and philosophical!) problem. It's not in general possible to tell the "true" number of clusters from continuous data without making a lot of assumptions about the processes that generated the data in the first place. So as others have said, the existence of population structure -- which definitely exists in humans -- doesn't necessarily imply discrete clusters.
On the one hand, it definitely seems to be possible to tell by genotyping that African-Americans generally have (quite different degrees of) both European and African ancestry, for instance, while white Americans have almost exclusively European ancestry with very little African admixture. This is possible because African populations and European populations drifted separately for quite a while pre-slavery. On the other hand, a pretty recent study of admixed Latin-American populations concluded that while factors like skin pigmentation were very important for racial self-identification, in the same populations, physical appearance was also not a reliable proxy for genetic ancestry.
"Population structure" or "population genetic structure" might be decent key phrases to search.
posted by en forme de poire at 7:15 PM on April 11, 2017 [3 favorites]
Not a population geneticist, but: I think you mean "haplogroups" (my understanding is that haplotypes are groups of genes inherited from a single parent, and haplogroups are clusters of similar haplotypes that share ancient polymorphisms on either the mitochondrial DNA or the Y chromosome).
Also, the fact that people can be clustered into ~20-ish haplogroups doesn't mean that this is the "true" number of ancestral populations or whatever; it's just one way of carving up the data. Depending on the question you're asking, finer- or coarser-grained groupings might be more appropriate. In general, clustering is a fraught statistical (and philosophical!) problem. It's not in general possible to tell the "true" number of clusters from continuous data without making a lot of assumptions about the processes that generated the data in the first place. So as others have said, the existence of population structure -- which definitely exists in humans -- doesn't necessarily imply discrete clusters.
On the one hand, it definitely seems to be possible to tell by genotyping that African-Americans generally have (quite different degrees of) both European and African ancestry, for instance, while white Americans have almost exclusively European ancestry with very little African admixture. This is possible because African populations and European populations drifted separately for quite a while pre-slavery. On the other hand, a pretty recent study of admixed Latin-American populations concluded that while factors like skin pigmentation were very important for racial self-identification, in the same populations, physical appearance was also not a reliable proxy for genetic ancestry.
"Population structure" or "population genetic structure" might be decent key phrases to search.
posted by en forme de poire at 7:15 PM on April 11, 2017 [3 favorites]
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posted by AFII at 7:02 AM on April 11, 2017 [3 favorites]