Category Archives: Actually serious for once

DNA Day and Body Modification

The scientific study of human heredity has and has always had two types of practical application: relief of suffering and human improvement. Research programs with those ends in mind have existed at least since the beginning of the 20th century—maybe earlier, depending on how you define things. But by the Progressive Era (roughly 1890–1920), research in human heredity and genetics explicitly sought to reduce or eliminate human disease, raise the average level of our intelligence, beauty, and longevity, and improve our character.

For a long time, the only way to accomplish those goals was to regulate behavior. At the highest level—i.e., the least invasive of bodies but the most invasive of liberty—you regulate the relationship between people who might have children together. In the Progressive Era, many states passed laws prohibiting marriage between two people who were mentally retarded, or certifiably insane, or had tuberculosis (though its infectious nature was recognized, researchers also understood that there was an inherited predisposition). Immigration restriction laws, too, were a form of regulating behavior in the supposed interest of the national heredity (at least in part). They can’t breed if you don’t let them in in the first place.

Many people at the time saw surgical sterilization as much less invasive than marriage or immigration restriction. Advances in surgical technology and practice shifted the target of modification from the relationship to the individual. Modify the individual body and you can afford to be unconcerned with who that person marries or lives with or next to. From our perspective today, sterilization is an appalling invasion of autonomy, but in the 1930s, the heyday of eugenic sterilization—worldwide, by the way, not just in Germany—many people saw it, like abortion, as a way to loosen restrictions on the behavior of the sick, imperfect, and impure while still working toward improving society.

For a long time, then, “applied” human genetics was synonymous with what we think of as the worst excesses and sins of eugenics. Science historians and historically minded scientists have often written that human genetics got “tangled up” with eugenics because the researchers back then did not have sufficient knowledge. Now that we understand the science better, the argument runs, we can avoid the kinds of simplistic fallacies that drove the eugenics movement—fallacies such as the idea that there is a single gene for “feeblemindedness.” Or, ahem, the love of the sea.

But that argument gets it backward. Eugenicists resorted to marriage laws and sterilization for the same reason that there was so little reliable data on human genetics: genetics required sex. Because human geneticists couldn’t carry out breeding experiments, they couldn’t do backcrosses, self-fertilizations, and all the other kinds of matings that other geneticists could do. They could, though, control who mated with whom to some degree on a broad social scale.

The significance of DNA is that it made it possible to do genetics without sex. It wasn’t just DNA, of course—cell culture as well as lots of advances in biochemistry and microbial genetics also contributed—but by the 1960s DNA had emerged as the emblem of a “new genetics.” From the beginning, the DNA double helix had an iconic aspect. The first published image, in Watson and Crick’s first paper (the anniversary of which is the impetus for DNA Day), had a stripped-down, cartoonish quality, and was described in the figure legend as “purely diagrammatic.” Everyone understands DNA, then, to mean much more than “deoxyribonucleic acid.” It stands for the relationship between heredity and health.

The new, DNA-based, molecular genetics finally made it possible to do genetics without sex. Reducing or preventing disease no longer required controlling who married whom, or (more theoretically) even which babies got born. Technology made it possible to select which genomes made it into the next generation, and even, in principle, to alter and “correct” genes in the individual.

“DNA” thus solved the fundamental ethical problem of eugenics. State-level involuntary coercion of reproductive behavior simply makes no sense in a developed country with sophisticated biomedical facilities. It is pointless and paranoid to fear a “return to eugenics” if what you mean is that good ol’ time Progressive eugenics.

In the DNA era, human genetics is still about relief of suffering and human improvement. The NIH touts the disease side of things, but what counts as a disease is heavily freighted with subjectivity, cultural bias, gender, and racial prejudice. Further, at the molecular level, the difference between preventing disease and genetic enhancement dissolves. If you up-regulate transcription of the gene for Human Growth Factor, for example, it makes no difference technically whether you do it in a dwarf, a short person, or a person of normal stature. And the moral distinction between remediation and enhancement relies on soft, unsatisfying philosophical arguments that basically amount to “Ugh!”—in the same way that a conservative parent reacts when his child comes home with blue hair and a lip piercing.

In 1957, Julian Huxley—grandson of Darwin’s bulldog, a distinguished biologist in his own right, and an articulate, politically liberal eugenicist—coined the term “transhumanism.” He wrote, “The human species can, if it wishes, transcend itself —not just sporadically, an individual here in one way, an individual there in another way, but in its entirety, as humanity.” This is what he defined as transhumanism, and he intended us to accomplish it by a variety of means, but of course at the root of it would be the conscious, deliberate manipulation of the human germ line. Throughout the 1960s, geneticists fantasized about using the new knowledge of the genetic code to control human development and evolution, to tinker with the design of human beings. The overwhelming majority of this fantasizing was done with the noblest of intentions. Huxley, JBS Haldane, HJ Muller, Joshua Lederberg, Edward Tatum—these were not ignorant fools but rather some of the greatest, most sophisticated minds in biology. They wanted not to rule the world but to reduce suffering and improve happiness, compassion, and noble achievement.

Muller’s eugenic scheme was called “germinal choice.” We’ve all heard of the Nobel sperm bank that William Shockley (inventor of the transistor) wanted to establish—that was Muller’s germinal choice. Present-day transhumanists prefer Muller’s term to “eugenics,” which is irritating because it requires so much explanation about how their eugenics isn’t the same eugenics as the bad old eugenics. But it’s eugenics. The only reason to deny it is the bad publicity the term gives you.

Transhumanists such as Gregory Stock and ScienceBlog’s own Eveloce tend to argue that genetic enhancement is coming whether we drag our feet or not, and they may be right. The sociotechnical power of contemporary biomedicine is astonishing—and on the rise. I’m not yet sure how I feel about this. I am inherently suspicious of any structure with such a concentration of technological and economic power, and power leads to hubris. It is a truism that 21st century DNA science has the potential for enormous benefit as well as catastrophic harm.

The problem is that the largest benefits tend to be long-term, while the largest risks are in the short term. It is not paranoid to be worried about such a situation, nor is it inconsistent to enjoy and admire positive results as they come out while maintaining a healthy, grouchy skepticism about the larger project.

I’m actually encouraged by the fact that transhumanism has a significant overlap with the blue-dreads-and-lip-piercing set. I’m more comfortable with tweaking our genes to, say, be able to grow horns or have Mr. Spock ears than to make everyone tall, white, and smart. Sure, it can be trendy and pretentious, like other body modification subcultures such as the “modern primitives,” but at bottom these folks are interested in it as a form of expression, not social control. Anything that breaks down barriers rather than reinforcing them gets my vote.

 

Anti-determinism on the march!

Nice piece today from SciCurious, guest blogging over at Scientific American. The post is an analysis of a recent article in Nature claiming that by knocking out serotonin in two different ways (both neurotransmitter production and receptors), they abolished sexual preference. The mice apparently mounted either sex with equal frequency.

SciCurious does a beautiful job dissecting the assumptions in the Nature article, analyzing the data, presenting alternative hypotheses, and looking at the history of the research. For example, the authors might have merely lowered the threshold of sexual activity–an extension of “all girls get prettier at closing time”. Or perhaps the researchers influenced the perception of other cues, for example olfactory cues. “So does this paper prove that there are drastic increases in sexual behavior associated with low serotonin?,” SciCurious writes. “Absolutely. Does it show that low levels of serotonin change sexual PREFERENCE? Well, that’s difficult to say.”

Also, Ed Yong looked at the article from a different but equally skeptical point of view. He points out how difficult it is to translate these kinds of behavioral findings from mice to humans. Further, he writes, “serotonin isn’t all about sex.” When I was a teaching assistant for the Neural Systems and Behavior course at Cornell back in the late 1980s, we used to drill in to the students’ heads the idea that neurotransmitters do not have behaviors. They act in many regions of the brain and influence all sorts of behaviors in ways that are very far from straightforward.

Yong worries (rightly) that anti-gay groups will use findings like this to argue for a simple biological basis for homosexuality, perhaps even proposing serotonin therapy as part of their effort to “cure” it. And SciCurious links to news stories soon appeared suggesting that the researchers had “turned mice gay.”

Such stories illustrate a fundamental fallacy that is one of the gravest dangers of popularizing science. For the sake of argument, let’s say the researchers did in fact eliminate sexual preference. In what sense is “no sexual preference” the same as “gay”? Ans: only in a world so normative that strict, unwavering heterosexuality is the only behavior considered normal. Of course, there are lots of people like that–I read about them all the time. But it is blinkered, naive, and deeply chauvinistic.

Biological and especially genetic explanations of behavior are a double-edged sword. The gay community has oscillated in its support for research to find “gay genes” and other traces of the biological basis of homosexuality. If homosexuality is innate, the reasoning goes, then it is cruel and pointless to try to “cure” gays, in the same way it was cruel to “cure” left-handed people.

But “gay” is a cultural construct. There were no “gays” in Ancient Rome or in 19th century Paris, and there are no gays in the Foré of Papua New Guinea. Here and now, in our culture, we need the term in order to protect human rights that are trampled on by people unreflectively absorbing an outdated cultural taboo on homosexual activity. But in the long run, the ideal should be to get rid of the concept–for us all, in short, to be “gay-blind.”

Good skeptical science writing helps that cause, because it exposes fallacies in the ways we think about science. I’m fine with describing a physiological mechanisms for a behavior, but we need to be careful not to equate mechanism with cause. I’m wary of science writing that talks about the “roots” or the “basis” of complex behavior or disease. It implies a hierarchy that blinds us to many biological mechanisms that work in the other direction. In biology, cause and effect go both directions: behavior changes gene activity as much as gene activity changes behavior. Studies purporting to examine the biological “basis” of behavior rely on cross-species analogies and make unsupportable assumptions about motivation.

In short, a “gay” mouse is a ludicrous concept.

 

 

Thalassophilia unmasked

There is no gene for thalassophilia—yet, anyway.

My satirical post last week about scientists finding a gene for love of the sea was intended to make a point about how we view genomics today—and a historical point about how we smugly congratulate ourselves on being so much more sophisticated than early human geneticists and eugenicists. Most people got that it was a spoof, but I thought it would be worthwhile to discuss some of the deeper issues at stake.

Charles Davenport was a real scientist, and the quotes from him are real. Davenport was a geneticist in the first half of the 20th century and the leader of the American Eugenics movement during the Progressive Era. He is often demonized as wrong-headed, misguided, and simple-minded. Indeed, he could be all of these things. Davenport really did believe there was a recessive, male-linked trait for the love of the sea. Thalassophilia has become a classic example of how eugenicists could ignore obvious environmental explanations in favor of the hereditary. When I told my 11-year-old daughter about Davenport’s thalassophilia, she immediately saw the fallacy: the sons of ship captains learn their love of the sea, they don’t inherit it.

My larger point is that simplistic analyses like Davenport’s can be masked by numbers and fancy technology.

For years, medical genetics involved the search for genes underlying genetic disease. Diseases that were caused by a defective gene, and not, say, by a germ or some other environmental factor. But that distinction has been erased. We used to think of genetic traits and non-genetic traits. Now, non-genetic traits are called “complex”—i.e., partly genetic and partly environmental. In other words, all diseases, and indeed all traits are understood as partially genetic.

There are sound reasons for thinking this way. I’m not arguing that those genes don’t exist. I don’t question the data—I’m happy to believe that there really is a genetic association with all of these traits. Indeed, I think it’s becoming possible to find a real, verifiable genetic basis for almost anything you like.

The advent of genome-wide association studies (GWAS) has made it vastly easier to examine traits with smaller and smaller genetic contributions. In essence, you can pick your trait, sample the DNA of a large group of people, and scan their genomes for bits of shared sequence.

As a consequence, we have the recent bloom of studies describing the genetic component of all sorts of “complex” traits, from religiosity to getting drunk and beating people up. We’re only limited by our imaginations, and by the kinds of traits we’re interested in today.

Thinking about these recent studies, it occurred to me that these traits were not fundamentally different from Davenport’s old favorite, thalassophilia. I bet, I said to myself, that if sailing were as culturally important today as it was in 1919, people would be doing GWAS to find the genetic basis of sea-lust. And I bet they’d find it.

Of course, there are big differences between human genetics in 2011 and human genetics in 1919. Davenport advocated sterilization laws and immigration laws to manage and shrink what he saw as the swelling populations of the “unfit.” That would be inconceivable today. I don’t think we’re returning to a “new eugenics” in any meaningful sense.

But cutting across the cultural differences are some continuities. One of them is the desire to believe there is a simple genetic explanation for our tastes and talents. That I think is a dangerous view. So on the one hand, I think we should be careful to evaluate 1920s science by the standards of the day, rather than by those of the 21st century. And on the other, we must not delude ourselves that modern science is completely objective. Mechanistic explanations are not proof against cultural bias.

My spoof was intended as a word of caution, a way to inject a note of skepticism about genetic explanations of human nature. C.M (“Call Me) Ishmael, the journal Genetic Determinism Today, MysticGene, the 4C (“for sea”) variant, the salt-stained polo shirts and the sailing widows—all that was pure balderdash. As the motto of this site goes, “Here lies truth”— in roughly equal measure.

So, keep your heads up, folks—and watch for the keyword “Satire” in the Categories section of this blog. Thanks for reading.