by Patrick Appel
Nicholas Wade’s A Troublesome Inheritance: Genes, Race and Human History, which I finished reading last night, is a deeply flawed examination of human genetic difference. Andrew, who is more sympathetic to the notion of race as a biological construct than I am, often does not see eye-to-eye with me on matters of race and genetics. But he encouraged me to critically examine Wade’s book during this guest-blogging stint in order to move the conversation forward. Andrew will likely respond to the debate when he returns next week.
The best refutation of the book I’ve seen is comes from Agustín Fuentes, a professor of anthropology at Notre Dame. In an hour-long webinar hosted by the American Anthropological Association, Fuentes debates Wade and takes a jack-hammer to the factual foundation of Wade’s book. Alex Golub summarizes the Fuentes-Wade exchange for those who don’t have time to watch it. A key part:
Fuentes pointed out that “genes matter” but that “they’re just a small part of a whole evolutionary picture” which results in behavior. He also argued that Wade was imprecise in his terminology. “Wade uses cluster, population, group, race, sub-race, ethnicity in a range of ways with few concrete definitions, and occasionally interchangeably throughout the book” he said.
Fuentes then went on to deal with the topic of human genetic variation. Humans share all of their genes and 99.9 percent of variation, he said, so what was being discussed in the webinar was just “0.1 variation of all the variation in the genome.” He emphasized that “most variation in human genetics is due to gene flow and genetic drift, which basically mean that the further apart two populations are, the more differences there are going to be between them.” Wade relied on a study which showed differences between people in Nigeria, Western Europe, Beijing, and Tokyo which showed differences between these groups but, Fuentes claimed, if you studied people from Liberia, Somalia, and South Africa you would get similar variation. “So for zoologists,” Fuentes concluded, “no human populations are different enough from one another to be called subspecies.”
Fuentes argued that the color-coded clusters of genetic data that Wade used in his book were a product of arbitrary choices made by Wade and scientists, and did not emerge automatically in the data themselves. In one study, the computer program Structure was asked to cluster data into 3, 4, 5, and 6 groups. Fuentes claimed that Wade noticed the arbitrariness of this scheme in his book and decided on a five-race scheme because it was “practical for most purposes” and not because it was naturally there in the data.
Another important point:
[Debate host Ed] Liebow asked Fuentes to talk about how biological evolution is linked with social evolution. Fuentes stresssed that “rather than just the environment shaping organisms and their gene pool, we know there’s interaction between organisms and the environment, which actually changes the way natural selection works. Evolution is ongoing over time and complex, it’s not just the environment targeting genes.”
For Fuentes complexity was clearly important. “The representation of little teeny minor differences in some areas of the DNA and connecting that to large sociopolitical and historical differences as Nicholas Wade did in his book, it’s misleading because it’s not giving true credit to the complexity of evolutionary biology and the complexity of understanding how things evolve.”
Pete Shanks comments on the webinar:
It was not so much a discussion as a debate, and in my view Fuentes defeated Wade thoroughly, though it was all very polite (too polite). Fuentes was well prepared, and able to identify, cite and comment on every study that Wade brought up to support his thesis. More important, he kept hammering away at the definition of “race” — as in, Mr. Wade, can you tell us, what is it? If you are going to claim that certain kinds of genetic variation between populations constitute a racial grouping, how do you define it?
Mostly Wade ignored the question. To the extent that he addressed it, he dismissed it as unimportant. Whether there are three or five races, or more, and where the boundaries are drawn: these are mere details until we admit the possibility of discussing race. (I’m being a little kind to him here myself; he burbled.)
Wade is full of factoids; the impressive thing about Fuentes’ performance was that he was familiar with all of them. That inevitably led to some points of agreement. For instance, at one point, Wade started to speculate about what percentage of genetic divergence would constitute a sub-species, and zoologically, they were in broad theoretical agreement. However, Wade seemed to be edging towards very dangerous waters when it came to the concept of human sub-species. Unfortunately, Fuentes and moderator Liebow were too polite to shove him in.
Over at his blog, Fuentes writes that “dialogue on such an important topic should be encouraged and as open minded as possible, but it must also be accurately informed by the science of human biology.” He provides a “mini-primer on what we what we know about human genetics to help such a discussion”:
1) Genes matter, but they are only a small part of the whole evolutionary picture and focusing on DNA segments won’t get you very far in understanding human evolution. The roundworm C. elegans has about 20,000 genes and humans have about 23,000 genes—it is pretty obvious that humans are more than 15% more complex than roundworms.
2) When making scientific argument about genetic variation you need to focus on populations–and be clear about your definitions (a common one for “population” is a geographical cluster of people who mate more within the cluster than outside of it). Many people talking about this subject use the words cluster, population, group, race, subrace and ethnicity in a range of ways, with few concrete definitions and occasionally interchangeably. If you do not define something then you cannot measure it, test for it, or try to construct and refute or support hypotheses for it—in short you can’t do science.
3) Humans all share 100% same genes and 99.9% of the variation in the DNA. So the variation we are interested in is .1% of the entire genome. And yes, understanding that variation is important
4) Most genetic variation is due to gene flow and genetic drift so the further apart two populations are the more likely they are to have more differences
5) Nearly all the genetic variation in our entire species is found in populations just in Africa, with most of the variation found in all populations outside of Africa making up a small subset of that variation.
He ends his post with these words:
We do need to talk about Race without fear and with clarity. We certainly need more public discussions on Race, not less. But in doing so we need to accurately represent what the social and biological sciences actually tell us about genetic variation, about race, and about evolution.
That is exactly the kind of discussion I hope to engage in over the course of this week’s guest-blogging. Readers are invited to help me deconstruct Wade’s book. Even though A Troublesome Inheritance is hugely problematic, the reviews and debate surrounding it are worth examining in detail. I will follow up on this post with a series of posts focused on individual fault-lines within the larger debate.