In Praise of Genetic Diversity

(photo courtesy of Nature)

(photo courtesy of Nature)

Bruce Lahn knew that his 2005 papers on the recent evolution of brain genes might stir up some controversy. In the journal Science, the University of Chicago professor of human genetics and his colleagues studied two genes involved in regulation of brain size during development. Intriguingly, they found variants of these genes that are favored by natural selection and are more prevalent in some geographic groups than others. Despite caveats about the complex, multi-dimensional nature of genetic differences, Lahn expected that people on the fringe might twist his research to justify racist beliefs. But he was  surprised at the degree of controversy, particularly the negative reaction from other scientists who distorted his conclusions to make straw-man arguments and even questioned the worth of doing such research in the first place.

That experience, Lahn says now, made him wiser about the way that human genetics research is interpreted by the public and even his scientific peers. But rather than shy away from the type of research that provoked such hubbub, Lahn decided that scientists needed a new moral framework to deal with rapidly growing information about how genes differ between individuals and groups. In an opinion piece published in the journal Nature today, Lahn and co-author Lanny Ebenstein argue that scientists and society at large must embrace the idea of genetic diversity, rather than persist in the more palatable assumption, increasingly disproven by science, that there are no meaningful genetic differences between geographic and ethnic human groups.

“I think the danger really is in the moral attitudes of the people themselves,” Lahn said when we discussed his essay earlier this week. “Instead of trying to suppress the science we should try to build a moral consensus that is constructive to the overall well-being of the species. I think that’s what’s important.”

“The truth about human diversity cannot be changed, but attitudes can change,” he continued. “I think it’s better to change attitudes than to hide factual truths.”

Some scientists disagree, arguing that the danger of scientific research into differences between ethnic groups or races outweighs the potential benefits. In an essay published by Nature earlier this year, Steven Rose, a British neuroscientist, argued that studies of group differences in intelligence are not worthwhile.

“The problem is not that knowledge of such group intelligence differences is too dangerous, but rather that there is no valid knowledge to be found in this area at all. It’s just ideology masquerading as science,” Rose wrote.

Lahn, in his essay and in our conversation, argued that this kind of “biological egalitarianism” – the idea that there are no significant differences between ethnic groups – is in fact more dangerous than the potential misuse of human genetics research. Some scientists, he worries, may be pushed away from important research questions by fears over funding, job security or public opinion should they tackle a field considered to be controversial or unnecessary by their peers.

“People may choose to do or not to do certain types of research because of political pressure or pressure from the social, moral norms,” Lahn said. “I’d be very surprised if you study ethnic differences in humans versus Drosophila strain differences of memory, that [the projects] would be evaluated on equal scientific terms.”

However, as more is learned about the subtle genetic differences between individuals, scientists and clinicians are discovering that some grouping of individuals is, in fact, medically useful. A review paper published in August by Peter O’Donnell and M. Eileen Dolan of the University of Chicago addressed several different chemotherapy drugs that are known to have different effects, on average, in different ethnic groups. For example, a common drug called 5-fluorouracil used in treating colon cancer is more effective in Caucasian patients than African American patients. O’Donnell and Dolan concluded, similar to Lahn and Ebenstein, that “pharmacoethnicity research and the awareness it brings to acceptance of the similarities and differences between individuals…carries the hope of improving the ethics of how ethnicity is studied in clinical studies and our world.”

That acceptance may be aided by the fact that ethnicity research – often used historically to justify social prejudice – today can be applied to a positive goal: the customization of medical treatment to specific groups and individuals. Studies by laboratories using cell cultures taken from various ethnic groups around the world have identified key gene polymorphisms that can alter the toxic or beneficial effects of a drug, research that will be crucial to the growing, related fields of pharmacogenetics and personalized medicine.

“To intentionally overlook the influence of group diversity on disease susceptibilities and treatment outcomes is to practice poor medicine,” Lahn and Ebenstein write in their Nature essay.

The solution, the authors argue, is to convince people to accept genetic diversity much as appreciation of cultural diversity has grown over recent decades. In the essay, Lahn and Ebenstein point out that “genetic diversity is a source of evolutionary resilience and adaptability.” In my chat with Lahn, he uses a more casual example to illustrate the importance of genetic differences.

“I think it would be horrible if everybody started with the exact same genes as Einstein,” Lahn said. “He was a violin player, but there probably wouldn’t be hip-hop, there wouldn’t be great athletes. I don’t think Einstein would be a great politician. Who’s going to write the novels?”

Convincing scientists to adjust their attitudes about studies of genetic differences is actually the easier battle, given that Lahn’s arguments are increasingly supported by scientific research. But changing how the public perceives information about genetic differences between ethnic groups is a different matter – can a population where the very theory of evolution remains widely unaccepted be taught the nuances of polymorphisms and predisposition? Lahn, citing rapidly changing views about disability in American and China, said he remains optimistic that society will soon see genetic differences as a source of pride, not a tool for hate.

“Genetic diversity is a strength not a weakness of humanity,” Lahn and Ebenstein conclude in their article. “On the whole, humanity has been and will be stronger, not despite our differences, but because of them.”

(An interesting discussion of Lahn and Ebenstein’s essay is starting to take place here.)

About Rob Mitchum (526 Articles)
Rob Mitchum is communications manager at the Computation Institute, a joint initiative between The University of Chicago and Argonne National Laboratory.
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