This study shows centenarians to more often carry a variant gene that affects exonuclease 1 (EXO1), involved in some forms of DNA repair - adding some fuel to the debate over the significance of nuclear DNA damage in aging. At this stage researchers are turning up longevity-associated differences in genes at a much faster rate than progress in understanding how it all ties together and how important specific genetic differences might be. From the paper: "Human longevity is heritable with a genetic component of 25-32%. Variation in genes regulating the levels of somatic maintenance and DNA repair functions is thought to modulate the aging process and to contribute to survival at advanced age. We tested 92 non-synonymous SNPs in 49 DNA repair genes for a possible association with longevity in a sample of 395 German centenarians and 411 controls. The obtained association signal in exonuclease 1 (EXO1) was further investigated by fine-mapping and mutation detection, leading to the identification of the functionally relevant SNP rs1776180. Our detailed analyses revealed that the common allele (C) of this promoter SNP is significantly enriched in female centenarians. This finding replicated in 455 female French centenarians and 109 controls. ... Given the survival advantage that is associated with the C allele of rs1776180, EXO1 can be considered a candidate for a novel longevity-enabling gene."

Link: http://www.ncbi.nlm.nih.gov/pubmed/19698732