Multi-cellular organisms develop different tissues through cellular differentiation regulated by gene regulatory networks. Onthophagus beetles have emerged as a promising model organism in evolutionary/ecological developmental biology, due to the expression of certain phenotypic traits in response (e.g. presence or absence of horns) to different environmental factors (e.g., availability of water and nutrition during development). Identifying the genes involved in the differentiation of tissues according to gender and nutrition factors provides understanding of the molecular mechanisms involved in tissue development which in turn can be used to model the effects of toxic chemicals in water environments on the development of organisms. A large microarray experiment

was designed to assess the expression of genes in four tissue types of male and female beetles exposed to high and low levels of nutrition. We describe the analysis of the data from this study, which involved problems of multiplicity at several levels and which inspired the search for gene “signatures” that differentiated beetles in terms of their development. Such gene signatures can be measured efficiently and inexpensively, and enable the assessment, with improved sensitivity, of changes in water quality.

Keywords: False discovery rate; Model selection; Analysis of variance; Robust methods

Biography: Guilherme Rocha received his BA in Mechanical Engineering from the University of Sao Paulo in 1999, his MS in Economics from the Getulio Vargas Foundation in 2003 and a PhD in Statistics from University of California, Berkeley in 2008. He is interested in applications of Statistics to high dimensional data sets.