An interesting paper from the owner of senescence.info and collegues: "Numerous microarray studies of aging have been conducted, yet given the noisy nature of gene expression changes with age, elucidating the transcriptional features of aging and how these relate to physiological, biochemical, and pathological changes remains a critical problem. ... We performed a meta-analysis of age-related gene expression profiles using 27 datasets from mice, rats, and humans. Our results reveal several common signatures of aging, including 56 genes consistently overexpressed with age, the most significant of which was APOD, and 17 genes underexpressed with age. We characterized the biological processes associated with these signatures and found that age-related gene expression changes most notably involve an overexpression of inflammation and immune response genes and of genes associated with the lysosome. An underexpression of collagen genes and of genes associated with energy metabolism, particularly mitochondrial genes, as well as alterations in the expression of genes related to apoptosis, cell cycle, and cellular senescence biomarkers, were also observed. ... We suggest these molecular signatures reflect a combination of degenerative processes but also transcriptional responses to the process of aging." Supplementary data is available over at senescence.info.