TY - JOUR T1 - Conservation of expression regulation throughout the animal kingdom JF - bioRxiv DO - 10.1101/007252 SP - 007252 AU - Michael Kuhn AU - Andreas Beyer Y1 - 2014/01/01 UR - http://biorxiv.org/content/early/2014/09/02/007252.abstract N2 - Gene expression programs have been found to be highly conserved between closely related species, especially when comparing the same tissue types between species. Such analysis is, however, much more challenging over larger evolutionary distances when complementary tissues cannot readily be defined. Here, we present the first cross-species mapping of tissue-specific and developmental gene expression patterns across a wide range of animals, including many non-model species. Importantly, our approach does not require the definition of homologous tissues. In our survey of 32 datasets across 23 species, we detected conserved expression programs on all taxonomic levels, both within animals and between the animals and their closest unicellular relatives, the choanoflagellates. We found that the rate of change in tissue expression patterns is a property of gene families. Subsequently, we used the conservation of expression programs as a means to identify neofunctionalization of gene duplication products. We found 1206 duplication events where one of the two genes kept the expression program of the original gene, whereas the other copy adopted a novel expression program. We corroborated such potential neofunctionalizations using independent network information: the duplication product with the more conserved expression pattern shared more interaction partners with the non-duplicated reference gene than the more divergent duplication product. Our findings open new avenues of study for the comparison and transfer of knowledge between different species. ER -