Phillip Newmark seeks to understand how some animals can regenerate missing tissues. Newmark and his team study planarians, a kind of flatworm that can regenerate an entire body from fragmented parts – a process which relies on stem cells. The team investigates how stem cells are regulated to produce missing tissues and organs in the context of building a whole organism. Insights from their work on fundamental planarian biology led them to study schistosomes and tapeworms (types of parasitic flatworms), which rely on similar stem cells for their propagation. Learning how parasitic flatworms infect their hosts and reproduce inside them could lead to new strategies for controlling these devastating parasites infecting hundreds of millions of people.