Molecular traces of alternative social organization in a termite genome

Abstract

Although eusociality evolved independently within several orders of insects, research into the molecular underpinnings of the transition towards social complexity has been confined primarily to Hymenoptera (for example, ants and bees). Here we sequence the genome and stage-specific transcriptomes of the dampwood termite Zootermopsis nevadensis (Blattodea) and compare them with similar data for eusocial Hymenoptera, to better identify commonalities and differences in achieving this significant transition. We show an expansion of genes related to male fertility, with upregulated gene expression in male reproductive individuals reflecting the profound differences in mating biology relative to the Hymenoptera. For several chemoreceptor families, we show divergent numbers of genes, which may correspond to the more claustral lifestyle of these termites. We also show similarities in the number and expression of genes related to caste determination mechanisms. Finally, patterns of DNA methylation and alternative splicing support a hypothesized epigenetic regulation of caste differentiation.

Carbon dioxide receptor genes in cotton bollworm Helicoverpa armigera

“…1a) (Robertson and Kent 2009;Terrapon et al 2014). Lastly, we included five putative CO2 GRs from the termite Z. nevadensis (Terrapon et al 2014) (Supplementary Table 1).…”

“…Lastly, we included five putative CO2 GRs from the termite Z. nevadensis (Terrapon et al 2014) (Supplementary Table 1). Alignment analysis demonstrated that the CO2 GRs are conserved in many insect species (~40-90 % identity) except termite Z. nevadensis, which contains five orthologous genes of CO2 GRs but showed low (<30 %) identities compared to other known insect CO2 GRs (Supplement Table 1) (Terrapon et al 2014). …”

“…1a) (Robertson and Kent 2009;Terrapon et al 2014). Honeybees and blacklegged ticks are known to respond to CO2 physiologically, indicating they may have another pathway for CO2detection (Robertson and Kent 2009;Terrapon et al 2014).…”

“…1a) (Robertson and Kent 2009;Terrapon et al 2014). Honeybees and blacklegged ticks are known to respond to CO2 physiologically, indicating they may have another pathway for CO2detection (Robertson and Kent 2009;Terrapon et al 2014). In Drosophila, the ionotropic receptors (IRs) IR64a and IR8a work together to detect a drop in sensory lymph pH, which could be induced by a high concentration of CO2 in the environment (Ai et al 2013).…”

“…The successfully cloned GR ORF sequences were further subcloned into PIB/V5-His vectors (Anderson et al 2009;Briscoe et al 2013;Dahanukar et al 2007;Erdelyan et al 2012;Obiero et al 2014;Robertson and Kent 2009;Terrapon et al 2014). GenBank accession numbers of these genes can be found in Table 1.…”