May 26, 2011

François Jacob
Institut Pasteur
28 Rue Doct Roux
75015 Paris
01 45 68 80 00

Dear François Jacob:

I enjoyed your charming article (The Birth of the Operon François Jacob SCIENCE vol. 332 no. 6031 May 13, 2011 page 767) and illuminating history.  When I was at Harvard Medical School your Nobel Prize was showcased with an implicit, “At best, this is the kind of thing you can do.”

There was no mention then of “night science,” as you say, “A stumbling, wandering exploration of the natural world that depends on intuition as much as it does on the cold, orderly logic of ‘day science.’” 

I would never have thought I would have the audacity to write you, but I think I have an idea you might enjoy, a bit of night science if you will.  I would suggest suppressing any thoughts that might begin, “This is important,” or “What does this mean for civilization?” or “What does this mean to my loved ones.  Those paths will not lead you to friends.

We can agree on the principle of evolution.  It cannot proceed without speciation.  Darwin dismissed speciation (it took him a whole book) as “happenstance,” but this is not true.  It is a fundamental requirement of any sexually reproducing organism.  If it is tardy, that organism cannot compete for a newly opened niche with faster speciating forms. 

Speciation, near as I can tell, takes about 2,000 generations.  It may be 3,000, but for easy arithmetic let’s say it is 2,000.  So here is a valley in which there are rabbits.  Two siblings are born sharing an identical chromosome or critical part of a chromosome.  One hops across the valley.  It gets cold.  A glacier splits the valley.  2,000 generations the climate improves.  The 2,000th grandson of one of the rabbits meets the 2,000th granddaughter of the other.  They cannot have fertile offspring.  Speciation has occurred. 

Now say there are 1,000 rabbits in the valley.  That means there are 2,000 copies of this chromosome.  Mating is random.  Each generation those 2 chromosomes on average have on chance in 1,999 or say one in 2,000 of meeting its counterpart.  This will on average take 2,000 generations.  When they get together, they cannot have fertile offspring.  Since this is true of every chromosome in the valley, all the rabbits die. 

The logic is air tight, but is counter to observation.  A little field work will reveal that there are actually rabbits.  Evolution has found a way to cheat extinction while preserving speciation.  The only way is this: the population must be subdivided into smaller units that do very little breeding with other units.  Somehow the big population is subdivided.

Such subdivision is seen everywhere in nature.  Salmon make their way to their home brooks to mate with cousins. 

So this compartmentalization of populations into small, and I literally mean less than 1,000 strong, units is required for survival.  This need is so intense that nature is not willing to wait 1,000 generations for the ax to fall.  It stands ready to snuff out the population as soon as it transgresses the limit, whatever it really is.  So fertility is not sustained for a thousand generations.  It is cut off before 10 generations. 

Here are references that establish it. 

R. Sibly et al., Science 309 607 (2005). 
A. Helgason et al., Science 319 813 (2008).
R. Labouriau, A. Amorim, Genetics 178 601 (2008).
R. Labouriau, A. Amorim, Science 322 1634 (2008).

The Helgason article has the best numbers.  The effect is to rapid for DNA mutations; I believe the mechanism is epigenetic. 

For about 15 years I have had a handle on this, and have tried to drag it into the daylight.  When I first saw it, none of the key references had been published.  Much of my effort has been simply to try to point this out to experts whose work is related.  You can follow my footsteps by going to and seeing how many letters I have written.  (I do not think you will be unhappy in the company of such.  If you are, do let me know and I’ll remove this letter if it has already been posted or suppress it altogether if I have not already posted it.)

Although after 15 years I cannot claim to have turned this into day science I have grappled with it enough to be quite sure there is something there. 

I thought you might like it as a mental exercise and as assurance that, yes, there is night science out there yearning for the light. 

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