ABSTRACT: AGEMAP is an initiative of the National Institute on Aging (NIA) designed to study the aging process on mice with Caloric Restriction (CR) versus Ad Libitum (AL) diet. The aim of the AGEMAP project is to provide a valuable source of information about genetic influences involved in aging of the major organ systems. A total of 67 mice (C57BL/6) were sacrificed. Both male and female mice were divided in 7 categories based on the diet and the age. Four categories in ad libitum (1 month, 6 month,16 month and 24 month) and three categories in caloric restriction (6 month, 16 month and 24 month). In the current study we focused on gonads, using microarray hybridization (Agilent platform 44K array) to identify gene expression changes age-associated CR-associated, between young versus old mice at different time points. Keywords: development or differentiation design,replicate design,stimulus or stress design,time series design The experiment was done as time-course type. Four time points for mice on ad libitum diet (1 month, 6 month, 16 month and 24 month), and three time points on caloric restriction diet. For each time point we used two biological replicates. We analyzed gene expression patterns in ovaries and testes sampled from 1-, 6-, 16-, and 24-month-old C57BL/6 mice fed on AL and CR diets (Figure 1A and D). Mice were kept on an AL diet until 14 weeks of age and then split into AL and CR gonads . Two individual animals for each condition were used for the microarray studies. We examined a total of 28 samples (two AL ovaries at each of 1, 6, 16, and 24 months; two CR ovaries at 6, 16, and 24 months; two AL testes at 1, 6, 16, and 24 months; and two CR testes at 6, 16, and 24 months). These 28 samples were hybridized on whole-genome oligonucleotide microarrays bearing approximately 44,000 probes, representing 25,585 nonredundant genes with gene symbols (Additional file 1). The same RNA samples were used for quantitative reverse-transcription polymerase chain reaction (RT-PCR)