Common features of aging fail to occur in Drosophila raised without a bacterial microbiome

By comparing the transcriptomes of Drosophila raised either under conventional conditions or in the complete absence of bacteria, we find that 70% of the transcriptional changes that normally occur with age are actually adaptive responses to the microbiome, not unavoidable features of aging. In the germ-free state, these seemingly ‘age-dependent’ gene expression changes never happen. Total RNA was isolated from the heads of wild type Drosophila grown either under conventional conditions (3, 10, 30 and 45 days old) or in the presence of antibiotics (10, 30 and 45 days old). Genome-wide gene expression was assayed using Affymetrix DroGene 1.0 ST microarrays, and data was analyzed as described in the associated manusript.