Vieira, Filipe G.Forêt, SylvainHe, XiaoliRozas, JulioField, Linda M.Zhou, Jing-Jiang2015-11-262015-11-261932-6203http://hdl.handle.net/1885/16847Insects are the most diverse group of animals on the planet, comprising over 90% of all metazoan life forms, and have adapted to a wide diversity of ecosystems in nearly all environments. They have evolved highly sensitive chemical senses that are central to their interaction with their environment and to communication between individuals. Understanding the molecular bases of insect olfaction is therefore of great importance from both a basic and applied perspective. Odorant binding proteins (OBPs) are some of most abundant proteins found in insect olfactory organs, where they are the first component of the olfactory transduction cascade, carrying odorant molecules to the olfactory receptors. We carried out a search for OBPs in the genome of the parasitoid wasp Nasonia vitripennis and identified 90 sequences encoding putative OBPs. This is the largest OBP family so far reported in insects. We report unique features of the N. vitripennis OBPs, including the presence and evolutionary origin of a new subfamily of double-domain OBPs (consisting of two concatenated OBP domains), the loss of conserved cysteine residues and the expression of pseudogenes. This study also demonstrates the extremely dynamic evolution of the insect OBP family: (i) the number of different OBPs can vary greatly between species; (ii) the sequences are highly diverse, sometimes as a result of positive selection pressure with even the canonical cysteines being lost; (iii) new lineage specific domain arrangements can arise, such as the double domain OBP subfamily of wasps and mosquitoes.Rothamsted Research receives grant-aided support from the BBSRC of the UK. The authors thank Prof. David M. Shuker, University of Edinburgh, UK, who provided us with N. vitripennis. FGV was supported by a predoctoral fellowship SFRH/BD/22360/2005 from the ‘Fundac¸a˜o para a Cieˆncia e a Tecnologı´a’ (Portugal). This work was funded by grants BFU2007-62927 and BFU2010-15484 from the ‘Direccio´n General de Investigacio´n Cientı´fica y Te´cnica’ (Spain) to JR. JR was partially supported by ICREA Academia (Generalitat de Catalunya). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.© 2012 Vieira et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.amino acid sequenceanimalscysteineecosystemevolution, moleculargenomemodels, biologicalmodels, geneticmodels, statisticalmolecular sequence datamultigene familyolfactory receptor neuronsphylogenyprotein structure, tertiarypseudogenesreceptors, odorantsequence homology, amino acidwasps2012-08-2710.1371/journal.pone.00430342015-12-10