Vitellogenin Underwent Subfunctionalization to Acquire Caste and Behavioral Specific Expression in the Harvester Ant Pogonomyrmex barbatus

• DOI: 10.1371/journal.pgen.1003730
• Publication Date: 2013-08-16T04:25:44Z
• Authors: Miguel Corona; Romain Libbrecht; Yannick Wurm; Oksana Riba-Grognuz; Romain A. Studer; Laurent Keller
• Keywords: Vitellogenin; Subfunctionalization; Subfamily; Linepithema; Body plan; Functional divergence

The reproductive ground plan hypothesis (RGPH) proposes that the physiological pathways regulating reproduction were co-opted to regulate worker division of labor. Support for this in honeybees is provided by studies demonstrating potential workers, assessed levels vitellogenin (Vg), linked task performance. Interestingly, contrary have a single Vg ortholog and potentially fertile nurses, genome harvester ant Pogonomyrmex barbatus harbors two genes (Pb_Vg1 Pb_Vg2) nurses produce infertile trophic eggs. P. barbatus, thus, provides unique model investigate whether duplication ants was followed subfunctionalization acquire non-reproductive functions function behavior sterile workers. To these questions, we compared expression patterns analyzed phylogenetic relationships molecular evolution ants. qRT-PCRs revealed Pb_Vg1 more highly expressed queens workers foragers. By contrast, level Pb_Vg2 higher foragers than queens. Phylogenetic analyses show first ancestral gene occurred after divergence between poneroid formicoid clades subsequent duplications lineages leading Solenopsis invicta, Linepithema humile Acromyrmex echinatior. initial resulted subfamilies preferentially (subfamily A) or foraging B). Finally, subfamily A experienced positive selection, while B showed overall relaxation purifying selection. Our results suggest underwent caste- behavior- specific associated with functions, supporting validity RGPH