Yesterday's post at the Longevity Meme on research into great feats of bacterial DNA repair probable bears a few further references. The DNA Repair Special Interest Group is one of the NIH special interest groups:
The DNA Repair Interest Group is concerned with all forms of DNA damage and repair. As a major defense against environmental damage to cells DNA repair is present in all organisms examined including bacteria, yeast, drosophila, fish, amphibians, rodents and humans. The members of the DNA Repair Interest Group perform research in areas including DNA repair enzymology and fine structure, mutagenesis, gene and cell cycle regulation, protein structure, and human disease.
Amongst other material, you'll find a basic information on DNA repair mechanisms and how DNA repair fits into the bigger picture of cancer and aging:
Biogerontologist Aubrey de Grey has his own take on this topic in the context of developing a cure for aging - be sure to read it after perusing the DNA Repair SIG site.
There are two types of accumulating change that happen to our chromosomes as we age: mutations and epimutations. Mutations are changes to the DNA sequence, and epimutations are changes to the "decorations" of that DNA which control its propensity to be decoded into proteins. Luckily, we don't need to deal with these two phenomena separately, because we can obviate them both in the same way.
This is another of the areas of aging in which evolution has done the really hard work for us. We have an enormous amount of DNA, and the job of keeping it intact and functional is incredibly complicated. But evolution had to do it, so it has developed the necessary sophistication for us. We're particularly lucky in one way: evolution (since the emergence of vertebrates, anyway) has had one DNA maintenance problem that is far bigger than all the others, and that is to stop organisms from dying of cancer. Cancer can kill us even if one cell gets the wrong mutations (or epimutations), whereas any loss of function in any genes that have nothing to do with cancer are harmless unless and until they have happened to a lot of the cells in a given tissue. So, all those genes get a free ride -- they are already maintained far better than we need them to be in anything like a normal lifetime.
This means that we don't actually need to fix chromosomal mutations at all in order to stop them from killing us: all we need to do is develop a really really good cure for cancer.