All living organisms are vulnerable to invasion by genomic parasites called transposons. If unchecked, transposons wreak havoc, jumping from place to place in the genome, causing mutations in normal genes. However, cells have a remarkable defensive system that uses non-coding RNAs as guides to identify and represses genome invaders. In animals, a distinct class of non-coding RNAs called piRNAs suppresses transposons in germline cells, ensuring fertility and the faithful transmission of genetic material through generations. The piRNA pathway works through an elegant RNA- and chromatin-based circuit and is amazingly powerful at discriminating transposons from ‘good’ genes and at repressing invaders in the nucleus and the cytoplasm using different mechanisms. Research in our lab is aimed at four major goals:

• We seek to understand how defense systems operate across different organisms from bacteria to human. We study molecular mechanisms of non-coding RNA biogenesis and their function in regulation of gene expression.

• We use our knowledge of natural defense mechanisms to adapt them for genome and epigenome engineering applications.

• We study the link between chromatin and transcription and the post-transcriptional fate of RNA. We explore the hypothesis that chromatin marks and co-transcriptional events direct the fates of different transcripts.

• We work to understand the role that transposons plays in evolution, normal development and diseases states such as cancer.