Letter from Fritz Lipmann to Francis and Odile Crick
Lipmann here raised the question of whether evolutionary changes were chance events or were produced by biochemical mechanisms.
Lipmann cited as an example for the latter the symbiosis of microorganisms, as in the phagocytosis (the engulfing) of bacteria
by primitive cells.
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1976-06-16 (June 16, 1976)
Original Repository: Wellcome Library for the History and Understanding of Medicine. Francis Harry Compton Crick Papers
I am very sorry that it had to take so long for me to write to you and thank you for the very nice couple of days I spent
in Cambridge which you had organized so well for me. I have to thank Odile particularly for the exquisite food she cooked
for me. I liked your two houses and the garden across the road, a unique and quite imaginative manner of living.
The reason for the long delay is that on arrival at the airport something very unexpected happened to me, namely, I lost the
vision in my right eye. After arriving in New York a detachment of the retina was found which required prompt operation.
Fortunately, I fell into the hands of a good surgeon and already have almost full vision again in the eye. It has been a
trying time not being able to read and write for several weeks, and it was a disturbing end to a very pleasant visit to Europe
including the better part which I spent in England.
Now let me turn to something that has bothered me, namely, that you felt that the joining of different organisms in the eukaryotic
cell was a chance event. Yet, in most cases, what we see at present seems to me to be a "marriage of convenience",
and this was why I looked for a background in present-day examples, such as the case of the lichens where fungi + algae yields
a diversified group of symbionts. Essentially it seems that the initial reaction is a phagocytosis of bacteria or other cells
which serve as food in primitive eukaryotes. Thus, as I see it, symbiosis is the result of an abortive phagocytosis where
instead of being digested, the organism is more or less modified to become a helper since it can add to the metabolic means
of the host, for example, nitrogen fixation or photosynthesis (Cf. enclosed copy of a paper given at the Ochoa birthday festival
I am grateful to have been prompted by your doubt about seeing something special in this symbiotic aggregation to have spent
some time reviewing it. I hope that you might agree that often it may be choice rather than chance.