Francis Crick quotes

Francis Crick was a British molecular biologist, best known as one of the co-discoverers of the structure of DNA. His work, alongside that of James Watson, fundamentally changed our understanding of genetics and heredity. He also made significant contributions to neuroscience and the study of consciousness. Here are 79 of his quotes:

It is one of the more striking generalizations of biochemistry - which surprisingly is hardly ever mentioned in the biochemical textbooks - that the twenty amino acids and the four bases, are, with minor reservations, the same throughout Nature.

Francis Crick

It seems likely that most if not all the genetic information in any organism is carried by nucleic acid - usually by DNA, although certain small viruses use RNA as their genetic material.

Francis Crick

Rather than believe that Watson and Crick made the DNA structure, I would rather stress that the structure made Watson and Crick.

Francis Crick

It now seems very likely that many of the 64 triplets, possibly most of them, may code one amino acid or another, and that in general several distinct triplets may code one amino acid.

Francis Crick

If the code does indeed have some logical foundation then it is legitimate to consider all the evidence, both good and bad, in any attempt to deduce it.

Francis Crick

A comparison between the triplets tentatively deduced by these methods with the changes in amino acid sequence produced by mutation shows a fair measure of agreement.

Francis Crick

Attempts have been made from a study of the changes produced by mutation to obtain the relative order of the bases within various triplets, but my own view is that these are premature until there is more extensive and more reliable data on the composition of the triplets.

Francis Crick

It now seems certain that the amino acid sequence of any protein is determined by the sequence of bases in some region of a particular nucleic acid molecule.

Francis Crick

The meaning of this observation is unclear, but it raises the unfortunate possibility of ambiguous triplets; that is, triplets which may code more than one amino acid. However one would certainly expect such triplets to be in a minority.

Francis Crick

Both of us had decided, quite independently of each other, that the central problem in molecular biology was the chemical structure of the gene.

Francis Crick

We've discovered the secret of life.

Francis Crick

I wasn't aware of Chargaff's rules when he said them, but the effect on me was quite electric because I realized immediately that if you had this sort of scheme that John Griffith was proposing, of adenine being paired with thymine, and guanine being paired with cytosine, then you should get Chargaff's rules. I was very excited, but I didn't actually tell Chargaff because it was something I was doing with John Griffith.... This was very exciting, and we thought "ah ha!" and we realized - I mean what anyone who is familiar with the history of science ought to realize - that when you have one-to-one ratios, it means things go to together. And how on Earth no one pointed out this simple fact in those years, I don't know.

Francis Crick

An honest man, armed with all the knowledge available to us now, could only state that in some sense, the origin of life appears at the moment to be almost a miracle, so many are the conditions which would have had to have been satisfied to get it going. But this should not be taken to imply that there are good reasons to believe that it could not have started on the earth by a perfectly reasonable sequence of fairly ordinary chemical reactions. The plain fact is that the time available was too long, the many microenvironments on the earth's surface too diverse, the various chemical possibilities too numerous and our own knowledge and imagination too feeble to allow us to be able to unravel exactly how it might or might not have happened such a long time ago, especially as we have no experimental evidence from that era to check our ideas against.

Francis Crick

And so to those of you who may be vitalists I would make this prophecy: what everyone believed yesterday, and you believe today, only cranks will believe tomorrow.

Francis Crick

There is no scientific study more vital to man than the study of his own brain. Our entire view of the universe depends on it.

Francis Crick

You're nothing but a pack of neurons.

Francis Crick

Almost all aspects of life are engineered at the molecular level, and without understanding molecules we can only have a very sketchy understanding of life itself.

Francis Crick

Exact knowledge is the enemy of vitalism.

Francis Crick

The balance of evidence both from the cell-free system and from the study of mutation, suggests that this does not occur at random, and that triplets coding the same amino acid may well be rather similar.

Francis Crick

We are sometimes asked what the result would be if we put four +'s in one gene. To answer this my colleagues have recently put together not merely four but six +'s.

Francis Crick

How is the base sequence, divided into codons? There is nothing in the backbone of the nucleic acid, which is perfectly regular, to show us how to group the bases into codons.

Francis Crick

This seems highly likely, especially as it has been shown that in several systems mutations affecting the same amino acid are extremely near together on the genetic map.

Francis Crick