Once upon a time, a boy learnt the three tenets of cell theory.
I) All living organisms are composed of one or more cells
II) The cell is the basic unit of structure and organisation in organisms
III) All cells exist from pre-existing cells
He was fine with the first two, but the third one...the third one bugs him. If cells only arise from pre-existing cells, what gave rise to the first cell? Unbeknownst to him, the question would never leave his mind and would guide him in some of the most important decisions he will make later in life. As he learnt more about biology and later chemistry, he would try to answer this riddle with every new piece of information he comes across. While it was fun to entertain the thought that he was getting closer to the solution, reality was not that straightforward. There was a reason why the textbook did not contain any further information, nor any front-page news with the headline "Origin of Life SOLVED".
Though it never burned out, his curiosity on the subject had been reduced to an ember due to the lack of substantial fuel. That would change one day in his last year of high school. As he was flicking through the syllabus, familiarising himself with the topics he’d have to know by heart before exams, one module stood out above the rest: The Origin and Evolution of Life on Earth. To say he was ecstatic would have been an understatement. After half a decade of not knowing where to look, he was going to get his first leads.
Over the next few weeks, the boy learnt of how the great minds of history have tackled this fundamental question with the knowledge available to them. From theories of spontaneous generation to the postulation of cell theory (completed in 1855) and Louis Pasteur's swan-neck flask experiment (1859), from intelligent design to Wallace and Darwin's theory of evolution by natural selection (1858). It was nothing short of inspiring learning of the hidden mechanisms of the natural world and how they were discovered through experimentation and the scientific method.
But it did not quite scratch that itch. What gave rise to the first cell?
Soon after, the teacher covered the work of Aleksandr Oparin and J.B.S Haldane. Independent of one another, the two scientists hypothesised that organic molecules that constituted the formation of early life could be made from inorganic materials and energy sources available on the early Earth such as the Sun (late 1920s)(1). However, science thrives on empirical evidence which would not come into being for another 20 years.
In an experiment that could only be described as elegant, Stanley Miller, a graduate student at the time, simulated the water cycle and atmospheric chemistry on early Earth in what is known as the Miller-Urey experiment(2). Amidst a diverse array of other organic molecules, Miller and his mentor Harold Urey identified 25 amino acids, building blocks of proteins and enzymes. Their work was immediately recognised by the scientific community and gave rise to a new scientific discipline known as prebiotic chemistry– the study of how organic compounds formed and self-organised for the origin of life on Earth and elsewhere(3). It was at that moment that the boy realised– this is where he belongs.
The boy would later go to university for a bachelor degree in molecular biology with a minor in chemistry. During his time there, he kept his eyes and ears open for opportunities to conduct research on prebiotic chemistry. After a year and a half, a chance finally presented itself. It was a course where students conduct their own chemistry research project spanning one semester. As he looked through a long list of participating academics, only a single one was interested in the origins of life. There was no way he was missing out on such an opportunity. He contacted the academic and got accepted.
Over the next few months, he desperately juggled assignments for other courses while wrapping his head around new synthetic and analytical techniques. At times, it felt as if the liquid circulating through his body was pure coffee. As the semester drew to a close, there was word about a new academic being hired in the School of Chemistry. Unlike his current supervisor, whose main focus was medicinal chemistry, the primary focus of the new lecturer was chemical evolution, the study of how simple molecules react to form more complex and functional ones (and potentially to life itself) – the type that would occur in the presence of a diverse array of organic molecules, similar to the Miller-Urey experiment!
As the stars would align, the boy would stumble upon the new academic by chance one day when he was submitting an assignment. They arranged a meeting sometime later and his new supervisor got him to work on a publication he has been working on since his time at the Earth-Life Science Institute at Tokyo Tech. Fast forward almost three years later, the boy is still conducting research under the same supervisor, now as a first-year PhD student. And his journey is just beginning!
(1) Lahav, N. Biogenesis : Theories of Life’s Origin; Oxford University Press, 1999.
(2) Miller, S. L. A Production of Amino Acids under Possible Primitive Earth Conditions. Science (80-. ). 1953, 117 (3046), 528–529. https://doi.org/10.1126/science.117.3046.528.
(3) Cleaves II, H. J. Prebiotic Chemistry: What We Know, What We Don’t. Evol. Educ. Outreach 2012, 5 (3), 342–360. https://doi.org/10.1007/s12052-012-0443-9.