A fundamental problem in meta-analysis is how to systematically combine information from multiple statistical tests to rigorously evaluate a single overarching hypothesis. This problem occurs in systems biology when attempting to map genomic attributes to complex phenotypes such as behavior. Behavior and other complex phenotypes are influenced by intrinsic and environmental determinants that act on the transcriptome, but little is known about how these determinants interact at the molecular level. We developed an informatic technique that identifies statistically significant meta-associations between gene expression patterns and transcription factor combinations. Deploying this technique for brain transcriptome profiles from ca. 400 individual bees, we show that diverse determinants of behavior rely on shared combinations of transcription factors. These relationships were revealed only when we considered complex and variable regulatory rules, suggesting that these shared transcription factors are used in distinct ways by different determinants. This regulatory code would have been missed by traditional gene coexpression or cis-regulatory analytic methods. We expect that our meta-analysis tools will be useful for a broad array of problems in systems biology and other fields.honey bee | transcriptional regulation A hallmark of complex phenotypes is that they have many different intrinsic and extrinsic determinants, and phenotypic variation between individuals is shaped by the interplay between heritable genotypic factors and environmental conditions (1). Understanding a complex phenotype, therefore, requires knowing whether its different determinants are subserved by common or distinct molecular mechanisms. For a given phenotype, do the multiple determinants act in fundamentally similar or different ways?Both intrinsic and extrinsic determinants influence phenotypes through their effects on gene expression. For instance, intraspecific behavioral differences between individuals are associated with changes in the expression of hundreds to thousands of genes in the brain (2). Also, manipulations of genetic, environmental, and hormonal determinants of some of these behavioral differences can induce similar changes in gene expression (3). This manipulation leads to the hypothesis that multiple intrinsic and extrinsic determinants that influence the same behavior exert shared effects on shared transcriptional regulatory mechanisms, for instance, relying on the activities of the same sequence-specific transcription factors (TFs).Testing this hypothesis poses serious challenges: transcriptional mechanisms linking genes to behavior are not well-understood, and although it is increasingly common to obtain transcriptomic profiles for a variety of determinants of a complex phenotype, there is no existing tool that can directly test if specific cis-elements are activated in multiple transcriptomic states in a statistically significant manner. Some existing tools (4-7) have been widely used to search for associations in specifi...