Cross-sectional expression of select miRNA in different age groups. The dotted line shows the age of the discovery group (mean age 63) for differential analysis with centenarians (mean age 104). A) If differential expression is simply age-related, expression will increase with age. B) If the differential expression is longevity-related, patterns of youthful expression will be preserved in centenarians while its expression levels in control individuals decline with age. C) A cross-sectional expression analysis of hsa-miR-363* by quantitative RT-PCR showed the youthful preservation mode: its expression levels significantly decline with age in control individuals (p < 0.05), while centenarians maintain the expression levels of the youngest age group (50–60). The significance of expression differences was assessed by student’s t-test. Each age group had 5 individuals while centenarians had 12 individuals.