Sex Determination in Termites

The project entitled Sex Determination in Termites and Its Link to Social Organisation proposes to investigate closely the way in which the sex of an individual is determined in termites and how that is related to the formation of complex societies. Termites, similar to humans, possess XY sex chromosomes. This is different from other social insects, like ants and bees, where males hatch from unfertilised eggs and thus only have half the number of chromosomes as females. The first major goal of the proposed project is to characterise the termite sex chromosomes in detail to understand how they evolved and whether they played a role in the transition from solitary to social lifestyle. In a second step, the genes involved in the molecular pathway for sex determination will be investigated. As an X- linked gene has been suggested to determine caste fate in some species, the third aim of the project is to identify which genes influence the sex of an individual, as well as its caste. This project will use three species of termites that differ in their social complexity in order to study the link between sex determination and the evolution of eusociality. Recently published termite genomes will be used together with gene expression patterns in males and females of the different castes to answer these questions. Computational analyses using this data will then be complemented by laboratory studies where the expression of the sex and caste determining genes can be experimentally manipulated. It can then be assessed if these genes are really responsible for the morphological differences between males and females and among the castes. The results from this project facilitate further studies of reproduction and sociality of termites, which are of great economic and ecological importance. So far, no termite sex chromosome has been described in genetic details and this study will address this and present a comparative analysis of three species spanning the different types of lifestyle found in termites. In addition, all research on the link between between caste and sex determination only comes from observations and crossing experiments. This project will shed light on this question how it works on a genetic and molecular basis. Overall, termites are the ideal system to study the evolution of sociality and the role that sex determination may have played in it.