2007 lecture

Physics Problems in Early Embryonic Development, William Bialek

Wednesday, May 23, Prof. William Bialek from Princeton University, United States, will present the Hendrik de Waard lecture. The lecture starts at 8 pm and takes place in the aula of the central university building, Broerstraat 5, Groningen. The lecture is aimed at a general audience and entrance is free for all.

Abstract

One of the most beautiful phenomena in nature is the emergence of a fully formed, highly structured organism from a single undifferentiated cell, the fertilized egg. Over the past decades, biologists have shown that in many cases the "blueprint" for the body is laid out with surprising speed and is readable as variations in the concentration of particular molecules. In the fruit fly, we know the identity of essentially all the relevant molecules. As we try to understand how these molecules interact to form the patterns that we recognize as characteristic of the mature organism, we face a number of physics problems. How can spatial patterns in the concentration of these molecules scale with the size of the egg, so that organisms of different sizes have similar proportions? What insures that the spatial patterns are reproducible from embryo to the next? Since the concentrations of all the relevant molecules are small, does the random behavior of individual molecules set a limit to the precision with which patterns can be constructed?

Although the phenomena of life are beautiful, one might worry that these systems are just too complicated and messy to yield to the physicists' desire for explanation in terms of powerful general principles. For the past several years, a small group of us at Princeton have been struggling with these problems in the context of the fruit fly embryo. To our delight, we have been able to banish much of the messiness, and to reveal some remarkably precise and reproducible phenomena. In particular, the first crucial step in the construction of the blueprint really does involve the detection of concentration differences so small that they are close to the physical limits set by the random arrival of individual molecules at their targets. This problem may be so serious that the whole system for constructing the blueprint has to be tuned to maximize how much signal can be transmitted against the inevitable background of noise, and this idea of tuning or optimization can be turned into a precise theoretical principle from which we can actually predict some aspects of how the system works.

My goal in this talk is of course to give a sense of what we have learned about one particular problem, but also I'd like to give some flavor of the fun we are having in exploring the interplay between physics and biology and between theory and experiment.

William Bialek

Born on 14 August, 1960 in Los Angeles, William Bialek moved to Berkeley to study Biophysics. He received his education at the University of California in Berkeley and obtained his bachelor in 1979 at the age of 19 with highest honors and distinction in general scholarship. He continued for his PhD at the same university and obtained his PhD degree in 1983, after which he moved to Groningen as a postdoctoral fellow. He returned to sunny California one year later as a postdoctoral fellow at the Institute of Theoretical Physics in Santa Barbara at the University of California. Clearly, the University of California at Berkeley kept track of his achievements and they promoted him to Assistant Professor of Physics and Biophysics in the year 1986. After five years at Berkeley he moved to the outskirts of Princeton, NJ to become a senior research scientist at NEC Research Institute. This Institute was founded in 1989 to do high risk, high pay-off basic research and is owned by the NEC Corporation in Japan. After a period of eleven years he went back to the academic world and started as a Professor of Physics at Princeton University in 2001.

A quick internet search at ISI Web of Knowledge for Bialek results in a long list of publications. Going though the list, standing out even more than the number of publications are the quality and popularity to the general audience of the journals. The highly prestigious interdisciplinary journals Science, Nature and PNAS appear more than once in the list of publications. However, even more striking are the titles of some of the publications. Are these publications in some kind of philosophical journal? This might come to mind if publications in the list have titles like Understanding the Efficiency of Human Perception [1], Bits and Brains: Information Flow in the Nervous System [2] and (perhaps even the most appealing title) Physical Limits to Sensation and Perception [3]. Indeed, some titles might seem to touch the thoughts of Greek philosophers. However, it is certainly all serious work and it reveals certain aspects and properties of our brain we never thought of before. Clearly, Bialek is interested in a broad set of problems that arise at the interface of physics and biology. With his experience and skills in theoretical physics and mathematics, he is describing processes from the biological world. He is a true interdisciplinary researcher, who also encourages the academic world to start more cross-talking and integration between different branches of research [4].

Next to being a very successful researcher, William Bialek has been awarded for his teaching. He received the s Award for Distinguished Teaching from Princeton University in 2006. Furthermore he wrote article in Science about a proposition to modify the current education system for 21st-Century biologist. Together with David Boltstein he describes why and how education for future biologist needs to be reformed in order to fully participate in modern biology research, which has changed fundamentally compared to the past. The bifurcation in science with on one branch mathematics, physical sciences, and engineering (where students are focused on principles and reasoning as the goal of their education) and on the other branch biology and medicine (where students are focused on mastering huge arrays of facts), does not provide the proper skills to live up to the requirements for a modern day biologist. Instead, they propose an integrated introductory curriculum in which physics, mathematics and biology are introduced together. Clearly, Bialek is very much involved in current educational programs and therefore trying to create a healthy situation for future researchers.

More information on William Bialek can be found on his homepage.

  • [1] Bialek, W. and Zee, A., Phys. Rev. Lett. 61, 1512-1515 (1988).
  • [2] Bialek, W., DeWeese, M., Rieke, F. and Warland, D., Phys. A 200, 581-593 (1993).
  • [3] Bialek, W., Annu. Rev. BioPhys. Chem. 16, 455-478 (1987).
  • [4] Bialek, W. and Botstein, D., Science 303, 788-790 (2004).