Ecological genomics of termites
Srini Kambhampati (PI); Matthew Steller and Joshua Urban (M.S. students)
Termites are eusocial insects that live in complex societies and exhibit reproductive division of labor. A colony consists of various castes that perform specific duties similar to individuals in honey bee and ant colonies. The morphological, physiological, and behavioral specializations are underlain by differential gene expression, i.e., a single genome gives rise to multiple phenotypes depending on the spatial and temporal gene expression pattern. The genome is influenced by social life in which social regulation of gene expression in turn influences behavior. Our goal is to investigate the genetic basis of eusocial life in termites. We are utilizing the eastern subterranean termite, Reticuliteres flavipes and adopting several approaches as follows:
1. Caste-specific EST libraries: We have constructed three caste-specific (workers, soldiers, and alates) cDNA libraries, sequenced ~15,000 clones and identified ~5,000 unigenes. We are fabricating 2,200 gene microarrays which will be used to study differential gene expression in the three castes.
2. Proteomics: We are using 2D-DIGE, Maldi MS-MS, and LC-MS to identify differentially expressed proteins in the heads of workers, soldiers, and alates. We have identified several proteins and in the process of identifying them.
3. Candidate gene approach: A number of brain-specific genes have been identified as being important in defining the behavior of honey bee castes. We are using degenerate PCR to investigate whether homologs of these genes are also present in termite brains. We then will use RNAi to investigate their function.
4. BAC libraries for targeted sequencing: We expected to obtain full sequences of genes that are differentially expressed in the above studies from a BAC library that was constructed to 10X coverage.
In the longer term, we expect to obtain the sequence for the entire transcriptome of R. flavipes, fabricate full transcriptome microarrays, undertake differential gene expression studies, and perform RNAi to silence specific genes to elucidate their function. We expect that our studies will provide insights into the genetic basis of eusocial behavior in an important insect and lead to comparative studies in which divergent eusocial insects can be compared for commonalities and differences.