[Note: This post is a modified and updated version of my earlier guest commentary on NPR 13.7 cosmos & culture]
For a long time, the origin of life was not considered a scientifically relevant problem. In fact, it was believed that life arises spontaneously all the time. Only after Louis Pasteur’s experimental demonstration that all life comes from other life, and the publication of Charles Darwin’s theory of evolution by natural selection (both around the middle of the 19th century), did the ultimate origin of life become a scientific question. However, it took (almost) another century before the first real scientific steps towards actually solving the problem were taken.
With an ever increasing understanding of many relevant topics in physics, chemistry, geology, and biology, research on the origin of life has seen a significant rise in interest as well as progress in the 21st century. This was exemplified at three major origin of life conferences held last year. I had the honor of being invited to speak at all three of them.
First, there was an international conference organized by the Princeton Center for Theoretical Science, at Princeton University in the USA. The notion of an “RNA world” was one of the main themes here. Then there was a workshop at CERN in Geneva, Switzerland. This mostly behind-closed-doors workshop focused on putting together a new set of research ideas and collaborations, and identifying potential funding sources. And finally, there was a conference at the Earth-Life Science Institute in Tokyo, Japan. This conference served as the inaugural event of this newly formed institute funded by the Japanese government.
What became clear at these meetings, is that despite the recent progress, there is still no real consensus on how life might have started on Earth. In fact, there is not even agreement on where it started. Hypotheses presented at these various meetings included:
- life was brought to Earth from outer space by meteorites,
- life started around alkaline hydrothermal vents on the ocean floor,
- life originated in shallow volcanic/sulfuric rock pools,
- life first appeared on the clay-surfaced ocean shores exposed to tidal wet-dry cycles,
- life came into being at sub-freezing temperatures on a snowball Earth.
Equally varied were the topics of the many presentations at these gatherings, such as (i) pure geochemistry and biochemistry, including various hypotheses about which elements were likely to have been abundant on the early Earth; (ii) the limits of life as we now know it, in terms of temperature, pH, pressure, salinity, etc.; (iii) attempts at reconstructing aspects of the last universal common ancestor (LUCA); (iv) the RNA world, a particularly hotly debated topic; (v) protein evolution and functionality; (vi) computer simulations of chemical systems; (vii) astrobiology, or the search for life on other planets and moons; and (viii) even a purely information-based approach.
My own presentation was on a formal framework for studying the emergence and evolution of autocatalytic sets, a collaboration with my colleague Mike Steel from the University of Canterbury in Christchurch, New Zealand, and largely based on the original ideas of Stuart Kauffman (who we also collaborate with).
However, what also became clear at these meetings, is that despite the current lack of full consensus on how or where life started, there is a growing optimism that the problem will actually be solved in the near future. Estimates range anywhere from 10 to 50 years from now, but no one seemed to doubt that the answer is within reach.
Indeed, the maelstrom of theory and research represented at these conferences is showing signs of coalescing into a clear way forward. More and more of the gaps and details are filling in with each year that passes. And in the process we are learning ever more about life in general, not just its origin.
Some of the research also leads to new technologies. For example, the work of David Deamer (author of the book First Life) has led to the development of a $900 pocket-sized DNA sequencer that plugs into the USB port of your laptop. And, of course, great medical advances are likely to flow from a deeper understanding of life’s origin and early evolution.
In short, even though there are still many (and some big) hurdles to overcome, origin of life research is clearly on the rise. And with a little bit of luck I’ll still be around to tell you about the solution to the problem, as a result of our collective scientific efforts. So make sure to check back regularly 😉