some thoughts on mutation
I general we also have to keep in mind that most mutations are quite innocent, because they have no effect whatsoever. This could be because the mutations occurs outside a gene, a promotor, enhancer elements etc.
Even if a mutation happens inside these important sequences the effect is most often zero. A single nucleotide can be mutated into another one, but the nucleotide triplet still encodes the same aminoacid for instance.
And even if the aminoacid identity is effected it might be an unimportant aminoacid. Not all areas in a protein are of the same importance for the function.
Even if a mutation causes a change in a protein which prevents its proper functioning there is no need for alarm. There could be another protein that can take over the function of the mutated protein. Or if it is an improtant protein the this particular cell just perishes.
Only if certain proteins are mutated at the proper place and the DNA repair mechanisms fail and the cell fails to give out signals saying 'KILL ME', then there is a chance of cancer. But usually there have to happen several mutation to several proteins in a single cell before a cell turns cancerous.
As you can see from all this the chances of cancer cells to develop are rather slim. This is reflected in the occurance rates of cancer compared to the enormous amounts of cells in our body.
Also mutations are beneficial on a different level: on an evolutionary level. Without mutations there would be less genetic variation and genetic variation is required if you want natural selection to select a beneficial trait. No mutations, no variation, no selection, no evolution, no life.
Therefore, despite the negative connotation that the word mutation has in the minds of most people, mutations are actually an essential and wonderful natural phenomonem.
