Social insect transcriptomics and the molecular basis of caste diversity.

Studies of gene expression provide fundamentally important information on the molecular mechanisms underlying variation in phenotype. Recent technological advances have allowed for the robust study of gene expression through analysis of whole transcriptomes. Here, we review current advances in social insect transcriptomics and discuss their implications in understanding phenotypic diversity. Recent transcriptomic studies provide detailed inventories of the genes involved in producing distinct phenotypes in social species. These investigations have identified key genes and networks involved in producing distinct social insect castes. Nevertheless, questions concerning the evolution of gene expression patterns remain. We suggest a path forward for studying gene expression in future studies of biological systems.

Evolutionary insights into DNA methylation in insects.

Epigenetic information affects gene function and plays a critical role in development. DNA methylation is one of the most widespread epigenetic marks and has been linked to developmental plasticity in insects. Here, we review the patterns and functions of DNA methylation in insects. We specifically focus on how the application of an evolutionary framework has led to important insights into the role of DNA methylation. We discuss the importance of evolutionary variation in DNA methylation among insect taxa and show how comparative analyses have revealed conservation in targets of DNA methylation. We then show how the distribution of DNA methylation in insect genomes has been linked to evolutionary conserved patterns of histone modifications and variants. We conclude by discussing how the evolutionary conservation and variability of DNA methylation in insects can provide insight into the function of DNA methylation across eukaryotic systems.