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A meta-analysis of differential coexpression across age. Jesse Gillis. Expression Analysis. Interpretations. Differential Expression Functional: Tissue differences Dysfunctional: Disease expression profiling Coexpression GO groups Differential Coexpression
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A meta-analysis of differential coexpression across age Jesse Gillis
Interpretations • Differential Expression • Functional: Tissue differences • Dysfunctional: Disease expression profiling • Coexpression • GO groups • Differential Coexpression • If functional association indicates coexpression then change in functional association would indicate change in coexpression • Tumor network vs normal network • Ageing involves many coordinated changes (functional and dysfunctional)
Theories of aging • Antagonistic pleiotropy • Early and late effects • P53 suppresses tumors and stem cells • Mutation accumulation • Decreased selection, extrinsic mortality predicting lifespan • cancer • Fetal programming • Maternal stress, cardiovascular risks • Senescence versus development • Often both
Background • Differential coexpression across age • Human microarray studies from Gemma’s database were categorized by their subject’s ages into the four groups • “prenatal” • “child/young adult” (0-18 years) • “adult” (19-54) • “older adult” (55+) • 8 to 13 studies for each age group • 2803 individual microarrays (repurposed) • Problem: How to generalize taking a difference to multiple conditions?
Wavelets and Differential Coexpression Separates Data into: Lifelong coexpression Lifelong change in coexpression Early life change in coexpression Late life change in coexpression Basis Set
GO group Validation Differential coexpression AUC 0.77 Coexpression values AUC 0.65 Random gene sets AUC 0.49 GO groups 25-30 genes leave-one-out-validation Take home message: Patterns of differential coexpression predict related fuction
SIRT1 -Longevity interest -Gene silencing in yeast -Unusual but repeated pattern -Early changes determine lifelong state
Ongoing Work • Disease groupings • Alzheimer’s • Schizophrenia • Aging patterns • Specific genes and theories • Finer aging gradations • Year by year
Acknowledgments • Paul Pavlidis and the Pavlidis lab • Support from NIH and the Michael Smith Foundation for Health Research