Friday, May 10, 2013

OF Flies Mice And Men- Francois Jacob 1920 -2013

The great French biologist Francois Jacob died on April 19th 2013. I started this post and left it lingering in draft. I want to post it now.

 Carl Zimmer at The Loom  has an essay which outlines one of the key moments of Jacob's career- when he realized how cells turn genes on and off.  That formed the basis of understanding gene regulation and laid the foundation of the field of developmental biology. For that work he shared the Nobel Prize in 1965 with Andre Lwoff and Jacques Monod.

Francois Jacob also wrote beautifully about evolution. His description of evolution as a tinkerer has become a popular way to think about how evolution builds novelties and puts together complex structures and traits. From his elegant essay on evolution and tinkering published in Science in 1977 :

Natural selection has no analogy with any aspect of human behavior, However, if one wanted to play with a comparision, one would have to say natural selection does not work as an engineer works. It works like a tinkerer - a tinkerer who does not know exactly what he is going to produce but uses whatever he finds around him whether it be pieces of string, fragments or wood, or old cardboards; in short it works like a tinkerer who uses everything at his disposal to produce some kind of workable object. For the engineer, the realization of his task depends on his having the raw materials and the tools that exactly fit his project. The tinkerer, in contrast, always manages with odds and ends. What he ultimately produces is generally related to no special project, and it results from a series of contingent events, of all the opportunities he had to enrich his stock with leftovers. As was discussed by Levi Strauss (5) none of these materials at the tinkerer's disposal has a precise and definite function. Each can be used in a number of different ways. In contrast with the engineers's tools, those of the tinkerer cannot be defined by a project. What these objects have in common is "it might well be of some use". For what? That depends on the opportunities.

I enjoyed reading his books; The Statue Within and Of Flies Mice and Men.

Here is a passage from his book Of Flies Mice and Men where he describes the fear and excitement of changing course midway through his career:

The word "courage" is not too strong. The daily interaction over years with a living organism, however humble, entails a certain familiarity. You could almost say that you acquire a certain tenderness for it. After 15 years of working with a particular colon bacillus, I had accumulated hundreds of mutants. In each of these mutants, one or another of the cellular functions, many of them indispensable to the life and reproduction of the bacteria, had been altered. To abandon this work and all that it offered; to renounce the kind of intimacy that comes with the knowledge of little unwritten quirks, the folklore that surrounds the work of any one organism; to start again from zero with another, unknown organism whose idiosyncrasies I would have to discover - all this was a considerable sacrifice. It was a little like leaving a loved one . But, at the same time, the new project was an exciting one. It would mean entering an unknown world, beginning a new life, becoming young again....

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