Solenn Patalano 1 , Anna Vlasova 2 , Chris Wyatt 3 , Philip Ewels 4 , Francisco Camara 2 , Pedro G Ferreira 5 , Claire L Asher 6 , Tomasz P Jurkowski 7 , Anne Segonds-Pichon 8 , Martin Bachman 9 , Irene González-Navarrete 2 , André E Minoche 10 , Felix Krueger 8 , Ernesto Lowy 2 , Marina Marcet-Houben 2 , Jose Luis Rodriguez-Ales 2 , Fabio S Nascimento 11 , Shankar Balasubramanian 12 , Toni Gabaldon 13 , James E Tarver 14 , Simon Andrews 8 , Heinz Himmelbauer 15 , William O H Hughes 16 , Roderic Guigó 2 , Wolf Reik 17 , Seirian Sumner 18
Nov 10 2015
Phenotypic plasticity is important in adaptation and shapes the evolution of organisms. However, we understand little about what aspects of the genome are important in facilitating plasticity. Eusocial insect societies produce plastic phenotypes from the same genome, as reproductives (queens) and nonreproductives (workers). The greatest plasticity is found in the simple eusocial insect societies in which individuals retain the ability to switch between reproductive and nonreproductive phenotypes as adults. We lack comprehensive data on the molecular basis of plastic phenotypes. Here, we sequenced genomes, microRNAs (miRNAs), and multiple transcriptomes and methylomes from individual brains in a wasp (Polistes canadensis) and an ant (Dinoponera quadriceps) that live in simple eusocial societies. In both species, we found few differences between phenotypes at the transcriptional level, with little functional specialization, and no evidence that phenotype-specific gene expression is driven by DNA methylation or miRNAs. Instead, phenotypic differentiation was defined more subtly by nonrandom transcriptional network organization, with roles in these networks for both conserved and taxon-restricted genes. The general lack of highly methylated regions or methylome patterning in both species may be an important mechanism for achieving plasticity among phenotypes during adulthood. These findings define previously unidentified hypotheses on the genomic processes that facilitate plasticity and suggest that the molecular hallmarks of social behavior are likely to differ with the level of social complexity.