March 8th was International Women’s Day, so I want to celebrate it (albeit somewhat belatedly!!) by writing about three of my favourite women scientists. Obviously there are so many more than just these three, and Em’s told the story of one of them here: Rosalind Franklin
Dorothy Hodgkin – The U.K’s only woman to have won a Nobel Prize in Science
As a biochemist, I can’t help but admire the work of Dorothy Hodgkin, who is famous for her work on the technique of X-ray crystallography. This technique is used to solve the structures of molecules such as proteins. Understanding the structure of a protein is important not only for understanding its role in an organism, but also for designing drugs to treat diseases. She is of particular significance at the University of Bristol where I’m doing my PhD, as she held the position of Chancellor from 1970 to 1988, and took an active interest in student life and the research going on here.
Dorothy Crowfoot was born in 1910 in Cairo, where her father was working at the time. Her parents had friends in the Sudan, one of which was the Chemist Dr. A.F Joseph, who sparked Dorothy’s interest in Chemistry and crystals from a young age. When she was 18 she went to study Chemistry at Somerville College in Oxford (named after Mary Somerville, a great mathematician of the time), and then went on to study for a PhD in Cambridge where she first started working on the X-ray crystallography technique.
After her PhD, Dorothy went back to Oxford, where she was appointed as a research fellow and tutor. She held this position from 1936 to 1977, and in that time inspired many young minds in addition to carrying out her own groundbreaking research. One of her students was the young Margaret Thatcher!
One of her most important projects was figuring out the chemical structure of Penicillin in the 1940s. At the time, world war was in progress and medical advancements were important. Knowing the structure of Penicillin has since allowed scientists to create a new arsenal of antibiotics based on its structure. In later years Dorothy turned her attention to Vitamin B12, where she further developed the X-ray crystallography technique and inspired other researchers to do the same. This technique is still used today to solve the structures of proteins.. Dorothy is also well known for her work on the structure of insulin, a much larger molecule than anyone had ever attempted before.
Ada Lovelace – The First Programmer
My partner is a computer scientist, and I am always amazed by the lines of code he churns out – as if he was born with the innate ability to do so – and even more amazed by what he can create with the algorithms that are the “recipes” of computer science. The person acknowledged as the creator of the first algorithm for a machine was Ada Lovelace.
Augusta Ada King, Countess of Lovelace, or now more commonly known as Ada Lovelace, was born in London in 1815 to Lord Byron, a poet, and Annabella, a mathematician who was dubbed the “Princess of Parallelograms” by her husband. Ada gained “Lovelace” from her husband William King, whom she married in 1835 and was later made Earl of Lovelace.
Ada showed interest in mathematics from a young age and her mother tutored her in the subject. Mary Somerville (remember her from earlier?) introduced Ada to Charles Babbage, a renowned mathematician and inventor.
At the time, calculators did not exist, and calculations were carried out by hand using printed mathematical tables. Charles invented a machine that could perform addition calculations, called the “Difference Engine”. In 1833, Charles had made a working portion of this machine, and put it on public display. When Annabella took a then teenage Ada to see it, Ada “young as she was, understood its working, and saw the great beauty of the invention”.
Before Charles could finish building his Difference Engine however, he came up with a new “Analytical Engine”, which was designed to handle more complex calculations. Unfortunately this was never built due to lack of funds. Nevertheless, Ada was fascinated by the designs – her reputation comes from a translation she published in 1843 of a paper written about the machine by Louis Menabrea, an Italian engineer, from French into English. Not only did she translate it, but she also added extensive notes of her own (the notes are reportedly three times as long as the actual translation!).
These notes included what is recognised as the first algorithm for use by a machine; hence Ada Lovelace is often referred to as “the first programmer”. She also speculated for the first time about the uses of these machines outside mathematics – the critical leap from calculation to computation – and outlined how the machine could be adapted to handle symbols and letters.
Unfortunately, Ada lived a short life and died in 1852 at the age of 36 from uterine cancer, and received very little recognition for her work during her lifetime, mostly due to the attitude of Victorian Britain towards women pursuing intellectual interests. Nowadays we celebrate Ada Lovelace Day every year, which this year will be held on the 15th October. The day is dedicated to the achievements women have made in science, and raises the profile of women scientists as role models for girls and women wanting to study STEM (Science, Technology, Engineering and Maths) subjects.
Zeros + Ones by Sadie Plant. Published by Fourth Estate; New Ed edition (1998)
“young as she was…” Sophia Freud, quoted in Ada, Countess of Lovelace by Doris Langley Moore, p.44
Barbara McClintock – Discoverer of Jumping Genes
During my undergraduate degree I did my final year literature project on “junk DNA” (or not-so-junk DNA, as it turns out – more on that in a later post), and came across the concept of “jumping genes”. These are pieces of DNA that can quite literally jump from one location in the genome to another, and are thought to make up 40% of the genome (Smit, 1999). Just to put this in context, less than 5% of our genome is what we consider “coding DNA”, which is the DNA that codes for proteins.
Barbara McClintock discovered these jumping genes (also called transposons or transposable elements) in the 1940s, and in 1965 was one of the first scientists to speculate that they regulate whether genes are switched on or off in the genome.
Barbara was born in 1902 in Connecticut, USA. She moved to New York in 1919 to study Botany at Cornell University, where she attended the only course in Genetics that was open to undergraduates. At that time, Genetics had not been widely accepted as a discipline, and only 21 years had passed since the re-discovery of Mendel’s principles of heredity. Barbara went on study graduate-level Genetics, and also a course in cell biology, which focused on the structure of chromosomes and how they behaved during cell division. Barbara enjoyed this immensely, and decided to dedicate the rest of her life to this field.
Barbara completed a PhD at Cornell, and post-doctoral research at the University of Missouri before moving to the Carnegie Institution of Washington’s Department of Genetics at Cold Spring Harbor on Long Island in 1940, where she remained until she retired in 1967.
During her research career Barbara focused on the maize genome, and spent time characterising its genes through extensive breeding experiments. She was intrigued by a mosaic-style colour pattern in the maize, and discovered that this was due to two jumping genes called “Dissociator” and “Activator”. Depending on when and where these move, a different colour of maize kernel is produced. This movement is random, and so the jumping genes would only move in some cells and not others – producing the mosaic effect.
The concept of jumping genes was not widely accepted by the scientific community at the time – it was to be thirty-five years after her discovery that she received the Nobel Prize in Physiology or Medicine in 1983.
Barbara was also the first scientist to correctly speculate about epigenetics – changes in whether genes are turned on or off that are not due to the underlying DNA sequence itself. While observing cells dividing, she noticed that different sets of genes were turned on and off in each of the cells, despite them being genetically identical.