In the February 18 edition of the Perpetual Notion Machine, we revisit the incredible and controversial process of gene editing. You may remember that we discussed gene editing with our guest Krishanu Saha, professor and scientist in biomedical engineering at UW-Madison (go to the January 21 post to hear the show). But we really just scratched the surface of this technology. So we invited Kris back to give us some detail into how CRISPR, and its scissor-cutting protein Cas9, can specifically target certain genes and edit them out. But we also wanted to discuss the risks and possible ethical concerns. So, Lynn Nyhart, the Vilas-Bablitch-Kelch Distinguished Achievement Professor in the History of Science, also joined us. There are some surprising similarities between the breakthrough of gene editing and both the development of genetically modified organisms (GMOs) and discovery of recombinant DNA.