Francis Crick Quotes

Unfortunately it makes the unambiguous determination of triplets by these methods much more difficult than would be the case if there were only one triplet for each amino acid.

A final proof of our ideas can only be obtained by detailed studies on the alterations produced in the amino acid sequence of a protein by mutations of the type discussed here.

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.

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.

That the primary effect of gene mutation may be as simple as the substitution of a single amino acid by another and may lead to profound secondary changes in protein structure and properties has recently been strongly indicated by the work of Ingram on hemoglobin.

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.

For simplicity one can think of the + class as having one extra base at some point or other in the genetic message and the - class as having one too few.

Our own genomes carry the story of evolution, written in DNA, the language of molecular genetics, and the narrative is unmistakable.

The study of the amino acid sequence around the disulphide bonds of the immunoglobulins was my own short-cut to the understanding of antibody diversity.

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.

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.

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.

Human insulin differs from other mammalian types by having a different C-terminal amino acid on the B chain. The immunological difference between beef insulin and human insulin, which is presumably responsible for the antigenicity of the former in some human beings, is thus limited to very a small portion of the whole molecule.

It would appear that the number of nonsense triplets is rather low, since we only occasionally come across them. However this conclusion is less secure than our other deductions about the general nature of the genetic code.

Humans are mutants, everything's a mutant - things that evolve.

Epigenetics doesn't change the genetic code, it changes how that's read. Perfectly normal genes can result in cancer or death. Vice-versa, in the right environment, mutant genes won't be expressed. Genes are equivalent to blueprints; epigenetics is the contractor. They change the assembly, the structure.

Transposons are just small pieces of DNA that randomly insert in the genetic code. And if they insert in the middle of the gene, they disrupt its function.

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.

DNA is a code of four letters; proteins are made up of amino acids which come in 20 forms. So the ribosome is a very clever machine that reads one language and operates in another.

The genome could be thought of as a kind of piano with twenty-five thousand keys. In some cases, a few keys may be out of tune, which can cause the music to sound wrong. In others, if one key goes dead the music turns into a cacophony, or the whole piano self-destructs.

Radiation is one of the important factors in evolution. It causes mutation, and some level of mutation is actually good for evolution.

It now seems to me that the findings of more than fifty years of DNA research have provided materials for a new and enormously powerful argument to design.

Mutations are exciting, there aren't nearly enough of them.

The genome is a book that wrote itself, continually adding, deleting and amending over four billion years.

Society's only real 'progressives' are the deviants and mutants. Look at evolution - fish who didn't deviate never became amphibians; frogs who didn't mutate never became reptiles; conformist snakes never became mammals , etc. Normal Humans will remain humans, and they'll be subjugated by the digital monsters of the next few millenia.