RT Journal Article SR Electronic T1 What to compare and how: comparative transcriptomics for Evo-Devo JF bioRxiv FD Cold Spring Harbor Laboratory SP 011213 DO 10.1101/011213 A1 Julien Roux A1 Marta Rosikiewicz A1 Marc Robinson-Rechavi YR 2014 UL http://biorxiv.org/content/early/2014/11/07/011213.abstract AB Evolutionary developmental biology has grown historically from the capacity to relate patterns of evolution in anatomy to patterns of evolution of expression of specific genes, whether between very distantly related species, or very closely related species or populations. Scaling up such studies by taking advantage of modern transcriptomics brings promising improvements, allowing us to estimate the overall impact and molecular mechanisms of convergence, constraint or innovation in anatomy and development. But it also presents major challenges, including the computational definitions of anatomical homology and of organ function, the criteria for the comparison of developmental stages, the annotation of transcriptomics data to proper anatomical and developmental terms, and the statistical methods to compare transcriptomic data between species to highlight significant conservation or changes. In this article, we review these challenges, and the ongoing efforts to address them, which are emerging from bioinformatics work on ontologies, evolutionary statistics, and data curation, with a focus on their implementation in the context of the development of our database Bgee (http://bgee.org).