A essay

CHAPTER 16

Science, Power, Gender: How DNA Became the Book of Life

Ruth Hubbard

Natural science, which is what we usually mean by science, involves interacting with nature in ways that produce certain kinds of interpretations of how nature works. There are different styles of doing science, depend- ing on what aspects of nature scientists are exploring, but all of them are constrained by rules of what constitutes evidence and what conclusions are considered permissi- ble. The different ways in which scientists pursue their work, however, do not easily fi t into male/female categories.

The fact that, in the United States, many more physicists are men than women has to do with the social and economic struc- ture of domestic life, with processes of education and professionalization, and with the social history of the disciplines, not with the intrinsic nature of physicists’ knowledge base or the nature of women and men. We live in a gendered society, and it should not surprise us if women and men tend to develop different tastes in the kinds of knowledge they seek and the ways they seek it, but this fact cannot be used to predict the practices of individual scientists. Besides, science imposes a he- gemony within which all its practitioners must operate if they want what they do to be acknowledged as science.

In this essay, I want to describe the contri- butions two outstanding women scientists

have made, in the course of the twentieth century, to our under- standing of how genes function and to raise the question of what ways gender can be said to have en- tered their scientifi c accomplishments and careers. But, fi rst, I need to review briefl y how, during this period, genes and DNA have come to be the iconic objects they currently are.

I

Genetics, of course, starts with the Czech monk Gregor Mendel. Using pea plants as his experimental objects, Mendel ex- amined the transmission of fl ower color and of the shape and texture of the seeds to successive generations. He deliberately chose discrete traits, such as red or white petals, or smooth or wrinkled seeds, rather than traits that vary continuously, such as weight or size. He also only kept track of the mathematical regularity with which these traits are transmitted and did not specu- late about what processes inside the plants are involved in transmitting the traits. He simply assumed that “factors” inside the plant mediate their transmission.

The publication of Mendel’s paper, in 1865, provoked little notice. But by 1900, when the paper was “rediscovered,” it aroused immediate interest. The reason

Women, Science, and Technology : A Reader in Feminist Science Studies, edited by Mary Wyer, et al., Taylor & Francis Group, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/osu/detail.action?docID=1386434. Created from osu on 2020-07-09 15:52:07.

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266 | RUTH HUBBARD

and phosphate and four different kinds of the “bases,” whose designations— A, G, T, and C— have become part of our ordinary vocabulary (as has the acronym DNA). It seemed hard to imagine how combi- nations of only these six subunits could specify all the different characteristics or- ganisms inherit from their parents. Protein molecules, by contrast, are composed of some twenty different subunits and come in many different shapes and sizes. It therefore was logical to assume that genes were made of proteins.

By the early 1950s, however, experi- ments with bacteria and viruses showed quite clearly that heritable characteristics are transmitted by DNA, not by proteins. Thus DNA was generally accepted as the substance that mediates inheritance— in a word, the gene.

II

This brings us to April 1953, when three papers appeared side by side in one issue of the British science weekly Nature. The fi rst, from Cambridge University, was co- authored by James D. Watson and Francis Crick; the other two, from King’s College, London, were authored by, respectively, Rosalind Franklin and Maurice Wilkins with their coworkers. The Watson and Crick paper announced the now- familiar double- helical structure of DNA. The other two offered evidence in support of this structure. James Watson has described how he and Crick arrived at the DNA struc- ture in his best- selling memoir, The Double Helix, published fi fteen years later, in 1968.

What immediately got scientists excited about the Watson- Crick model was that it can be made to explain how DNA— “the gene”— gets copied when cells replicate. The point is this: Let us picture the double helix as two railings of a spiral staircase, each of which is composed of a long, in variant sequence of sugar- phosphate-

is that, in the intervening years, scientists had learned a great deal about the inter- nal structure of cells and about what hap- pens when a cell divides and gives rise to two daughter cells. Stainable bodies, called chromosomes, had been observed in the cell’s nucleus, and scientists had noted that different cells of the same organism all contain the same number of chromo- somes. Scientists also noted that, when cells divide, their nuclear chromosomes split in two, which is how each daugh- ter cell ends up with the same number of chromosomes as were present in the par- ent cell. On the basis of such observations, by 1900 biologists accepted that chromo- somes have something to do with the way traits are trans- mitted from parents to offspring, and Mendel’s hypothetical “fac- tors” came to be conceptually associated with the chromosomes.

The Danish botanist Wilhelm Johannsen, in 1905, invented the word genetics to sig- nify biological inheritance, and, in 1909, he coined the word gene to lend more con- crete reality to Mendel’s “factors.” At a time when invisible atoms and quanta were being accepted into the world of chemis- try and physics, biologists had little prob- lem accepting that heredity is mediated by invisible material particles, carried on the chromosomes. And soon, as biological chemists came to identify all sorts of mole- cules that function in cells, one of the ques- tions they tried to answer was what kinds of molecules the chromosomes and genes are made of and how they function.

Once chemical analyses had shown that chromosomes contain two types of very large molecules, proteins and DNA, some scientists suggested that DNA provides the chromosomes with a structural framework to which proteins attach themselves to form the genes. What gave this model plau- sibility was that DNA, though very large, is a relatively simple molecule, containing large numbers of just one kind of sugar

Women, Science, and Technology : A Reader in Feminist Science Studies, edited by Mary Wyer, et al., Taylor & Francis Group, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/osu/detail.action?docID=1386434. Created from osu on 2020-07-09 15:52:07.

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267SCIENCE, POWER, GENDER |

of President Clinton’s referring to DNA as “the language in which God created life”— underlines the ideological content of mo- lecular genetics. 1

III

What relevance does all this have to gen- der? To answer this question, I want to look at the contributions two outstanding women scientists have made to our un- derstanding of genetics and DNA. I refer to Barbara McClintock and Rosalind Frank- lin. I have written about Franklin’s contri- butions before (Hubbard 1990, chap. 5), but as DNA has come to occupy not only a central role in biology but a larger- than- life role in the culture, certain elements of both her story and McClintock’s story have taken on new signifi cance.

Born in 1902 and dying in 1992, Bar- bara McClintock’s life spanned the twenti- eth century. She earned a Ph.D. in botany from Cornell in the early 1920s and stayed on at Cornell’s College of Agriculture on fellow- ships for several years, working on the structure of the cells and chromo- somes of corn (maize) and on its genet- ics. At Cornell, McClintock had access to a good- sized plot in which to breed corn. She needed that because she felt she had to get to know the individual, living plants if she was to make sense of what she ob- served when she later studied the detailed structure of their chromosomes under the microscope. 2 When it became clear that she was not going to be offered a position on the Cornell faculty, McClintock began to look around and eventually ended up accepting an assistant professorship at the University of Missouri. There she spent a few scientifi cally productive, but other- wise not very satisfying, years. The facili- ties were not all that good, so she needed to maintain her plantings at Cornell and shuttle back and forth. She also did not in- teract too well with some of her colleagues,

sugar- phosphate- sugar- phosphate units. The two railings are connected by a regu- larly spaced series of rungs, which make them run parallel to each other. Each rung is composed of a pair of bases, and the ge- ometry of the double helix is such that, for two bases to form a rung, an A on one rail- ing must meet a T on the other and a G on one railing must meet a C on the other.

This geometrical requirement means that, when cells divide and their chro- mosomes and genes get copied, the two strands of the double helix need merely unravel bit by bit. The sequence of bases on one strand then specifi es the base se- quence for the synthesis of its partner. Thus, DNA (“the gene”) gets copied by vir- tue of the requirement that an A on one strand of the double helix meet a T on the other and a G on one strand meet a C on the other, an incredibly simple and excit- ing outcome.

Yet this very simplicity conceals a con- ceptual trap, because it led scientists to describe DNA as a “self- replicating” mole- cule. And this has endowed the gene with the supposed power of not just participat- ing in the metabolic and synthetic activities of cells and organisms but of mastermind- ing and directing them. But, of course, DNA does nothing of the sort. Without the metabolic activities of cells, DNA is neither copied nor does it participate in specifying traits. Indeed, left to itself, DNA is one of the most inert and stable molecules in bi- ology, which is why it can be isolated, still intact, from ancient fossils.

Only by ignoring the participation of the rest of the cell and organism have mo- lecular geneticists enshrined the magic of DNA— the autonomous, all- powerful gene that does not just specify traits but produces and controls them. The fact that biologists, who are not usually known for their religious commitments, have selected “the Holy Grail” and “the book of life” as their metaphors for DNA— not to speak

Women, Science, and Technology : A Reader in Feminist Science Studies, edited by Mary Wyer, et al., Taylor & Francis Group, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/osu/detail.action?docID=1386434. Created from osu on 2020-07-09 15:52:07.

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268 | RUTH HUBBARD

as seriously as they would have taken a male colleague of comparable experience and stature. The degree to which McClin- tock was something of an outsider and a loner in her scientifi c life (though she al- ways had close friends) probably also had something to do with gender. But the con- tent of her science?

Some people have suggested that Mc- Clintock relied more on intuition than do most male scientists. Probably so, but so do some men. In a recent biography of Henry Wallace, Franklin Roosevelt’s two- term secretary of agriculture and one- term vice president, who was a world- famous plant breeder (and founder of Pioneer- Hi- Bred, the foremost supplier of hybrid corn), I found the following story. Late in Wallace’s life, a group of New York writers and artists asked him to what he attributed his suc- cess as a plant breeder. Wallace responded, “Sympathy with the plant” (Culver and Hyde 2000, 518), quite like McClintock’s “feeling for the organism,” her phrase that Evelyn Fox Keller uses as the title for her biography.

IV

Rosalind Franklin’s is a much sadder story. Franklin was born in 1920 into an estab- lished Anglo- Jewish family in London. She graduated from Cambridge University during World War II with a degree in phys- ical chemistry and went to work doing war- related research on different confi gu- rations of carbon in coal. At the end of the war, she moved to Paris and took a position in a French government laboratory, using X- ray diffraction techniques to analyze the structure of different types of coal. After four happy years there, she reluctantly de- cided to return to England and, because she wanted to learn about molecules of bi- ological interest, accepted a fellowship in the biophysics unit at King’s College, Lon- don, directed by Professor John Randall.

nor did she particularly enjoy teaching. When she was passed over for promotion, she felt it was time to move on. With strong support from older, established (male) col- leagues, McClintock was invited to spend a year at the laboratory of the Carnegie Institution at Cold Spring Harbor, Long Is- land, and it became her permanent home. McClintock’s lack of academic success did not stand in the way of her recognition within the profession. She was elected vice president of the Genetics Society of Amer- ica in 1939 and its president in 1945. More important, she was elected to the National Academy of Sciences in 1944— only the third woman member since its founding by President Lincoln. And she won a Nobel Prize in 1983— only the second woman sci- entist to win an unshared Nobel, the other being Marie Curie.

From the start, McClintock made path- breaking contributions. But since she was committed to looking at genes in the con- text of the whole organism, which was not the usual perspective in her fi eld, many of her fellow geneticists simply did not un- derstand her experiments or the way she interpreted them. When she concluded that genes can change their positions on the chromosomes, along with their func- tions, in response to changes within the plant and around it, this was so contrary to what geneticists believed possible at mid- century that many of them simply wrote her off. Not until the 1970s and 1980s, when comparable observations were made with bacteria, was what McClintock had been saying accepted into the canon of the fi eld.

So what does any of this have to do with gender? Certainly, McClintock’s failure to be promoted within academia had a lot to do with it, though it must also be said that she was not an easy colleague; but neither are many male academics. That colleagues chose to ignore her rather than make the effort to understand what she was saying suggests that they may not have taken her

Women, Science, and Technology : A Reader in Feminist Science Studies, edited by Mary Wyer, et al., Taylor & Francis Group, 2013. ProQuest Ebook Central, http://ebookcentral.proquest.com/lib/osu/detail.action?docID=1386434. Created from osu on 2020-07-09 15:52:07.

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