The budding lady botanist - Harriet Creighton
Barbara McClintock, left, and Harriet Creighton
The 1920s was a tough time to be a female scientist. Most women working in science at the time were either laboratory assistants or teachers and lecturers, rather than being allowed to pursue their own line of research or – heaven forbid! – run a laboratory. Yet there was one field that seems to have been slightly more accepting than others: botany, or the study of plants. We’ll talk about another pioneering plant geneticist, Edith Rebecca Saunders (who was also the co-founder of The Genetics Society) in more detail in a future episode.
But for now, imagine yourself at Cornell College of Agriculture in Ithaca, upstate New York – nestled on a bend in the river just south of the great glacial Cayuga Lake and surrounded by acres of gardens and plantations.
It was a perfect spot for any budding lady botanist, and Barbara McClintock was no exception. Many people - although not nearly enough – know about her work on maize corn and the discovery of so-called ‘jumping genes’ or transposons, which can hop around the genome, as well as her many other important findings about the nature of chromosomes and genes and how they behave inside cells.
But it wasn’t until 1983, when she was in her 80s, that she was finally awarded a Nobel prize in physiology or medicine – the first woman to win that prize as a solo scientist.
Although McClintock did pick up prizes and recognition for her work during her career, it wasn’t always easy, and she struggled to get tenure and funding for her research. In the end, she went to Cold Spring Harbor Laboratory in New York as a visiting fellow in 1941 and just never left.
This was partly because of her sex, partly because her ideas about genetics and fierce intelligence pitted her against the established dogma of the time and partly because, in the words of former Cold Spring Harbor director John Cairns, “She was [an] immensely difficult person who specialized in being difficult.”
But it’s not the story of Barbara McClintock I want to tell, but that of Harriet Creighton, her first graduate student.
It was summer 1929 when Creighton first arrived in the botany department at Cornell. She was a fresh-faced twenty-year-old who had just graduated from Wellesley College, a prestigious women-only institution in Massachusetts, where she had been taught by Margaret Ferguson – herself a graduate of Cornell, who claimed to have trained more botanists (and botanists’ wives) than anyone else.
Creighton had come to work as a graduate student and teaching assistant with one Dr Petrie, who specialised in paleobotany – that’s fossilised plants to you and me. As luck would have it, on her very first day she bumped into McClintock, who was then a graduate student working in the lab of Lester Sharp, and expert in cytogenetics – the study of chromosomes, the long strings of DNA inside living cells.
McClintock persuaded Creighton that it would be more interesting to study living plants than dead ones. By the end of the day her whole timetable had been rearranged according to McClintock’s advice. More importantly, she would switch over to working with Sharp, and should switch from being a master’s student to registering for a PhD. And even more importantly, McClintock would get to be her immediate supervisor.
This was a very cunning move on Barbara’s part. As someone who had only just received her PhD, she wasn’t really supposed to be supervising any students. But the pair clicked immediately, becoming friends and well as colleagues. McClintock set Creighton to work studying chromosomes in maize seeds, the two of them bunkering down in a small shared office and heading off to play tennis at the dot of 5 o’clock whenever the lakeshore weather permitted.
Creighton’s project was to investigate something known as ‘crossing over’, or recombination. Many geneticists at the time were perplexed by the observation that particular versions of genes, known as alleles, sometimes appeared to switch between chromosomes. This happened during meiosis, the special type of cell division that happens when sex cells are made – eggs and sperm in animals or pollen and ovules in plants.
Together, Creighton and McClintock showed that this was due to physical criss-crossing of chromosomes, which leads to bits of DNA being swapped around. Over in Berlin, fruit fly geneticist Curt Stern had made a similar discovery, but Barbara and Harriet beat him to publication by a matter of weeks, with their paper coming out in the Proceedings of the National Academy of Sciences in August 1931 while Stern was on vacation.
The renowned fruit fly geneticist Thomas Hunt Morgan had actually found out about Creighton and McClintock’s results when he went to Cornell to give a lecture and urged them to publish with haste. He later confessed that he had known about Stern’s competing data at the time, but nobly decided that maybe it was time that the women’s laborious experiments with slow-growing corn deserved the limelight ahead of fast-breeding fruit flies, who were getting all the genetics glory.
The high point of Creighton’s research career came in 1932 when she and McClintock attended the Sixth Annual Congress of Genetics, which was being held in Ithaca that year. McClintock gave a lecture about their work, and the two of them hosted a small exhibit explaining their discovery of crossing-over.
For Barbara, this was just the beginning, but for Harriet it was pretty much the end. Having observed how hard it was for McClintock and other women to secure a university position and funding for their research, she quit research in favour of a more financially stable teaching role at a women’s college in Connecticut, eventually returning to Wellesley as a lecturer in 1940.
She served in the US Women’s Naval Reserves – also known as the Waves – during the Second World War, then did stints teaching in Australian and Peru, before finally settling back at Wellesley until her retirement in 1974.
In her wonderful biography of McClintock, Evelyn Fox Keller describes Creighton as a “robust and easy-mannered woman, relatively tall… with a strong handsome face [and a] deep voice, made throaty by years of heavy smoking.”
It’s interesting to note that Creighton never married, although I can find no hints about her sexuality. But given that marriage for scientifically minded women usually meant trading independence and intellectual freedom for domesticity, it’s easy to see why she might not have been keen.
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