The gut microbiome – or the amalgamation of bacteria, fungi, archaea and viruses that reside in the digestive tract of living beings – is receiving a lot of attention from the scientific community. Many researchers say it holds important clues to human health, decoding which has led to its own slew of interventions, including pharmaceutical pills and fecal transplants. But the gut microbiome has undergone its own evolution, whose history is congruent with the enforced lifestyle and cultural changes brought about by colonization and migration. Today, we are in conversation with Dr. Fergus Shanahan, professor and chairman of the Department of Medicine at University College Cork (UCC), National University of Ireland, to understand the connections between the gut microbiome and the history of colonization. Dr. Shanahan is also the founder and director of the Alimentary Pharmabiotic Center (APC) in Cork, Ireland, which is among the largest gut microbiome research centers in the world. We are also speaking with Dr. Rupa Marya – a professor of medicine at the University of California, San Francisco, and founder of the Do No Harm Coalition, which is committed to addressing disease through structural change – to unpack how gut microbiota relates to radical acts of decolonisation, and what that means for the future of health and disease. In ‘The Missing Link,’ The Swaddle’s science podcast, we take a look at humanity’s most urgent questions – and the answers that might be lurking in unexpected science. Credits: Hosts: Rohitha Narharisetty and Ananya Singh Writing and Production: Rohitha Narharisetty and Ananya Singh Sound Design, Associate Producer: Vibhav Saraf Marketing Collateral Design: Hitesh Sonar Art Director: Neha Shekhawat Executive Producer: Karla Bookman