Bridget Kendall and guests explore the current understanding of how DNA works, why it needs constant repair in every living organism and how new DNA-altering techniques can help cure some medical conditions. Joining Bridget are Swedish Nobel Laureate and Francis Crick Institute Emeritus Group Leader Tomas Lindahl who pioneered DNA repair studies, medical researcher Niels Geijsen from the Hubrecht Institute who works on curing diseases caused by faulty inherited genes, evolutionary biologist T Ryan Gregory from Guelph University who asks why an onion has 5 times as much DNA as a human, and Oxford University’s bio-archaeologist Greger Larson whose research suggests that dogs were independently domesticated twice, on different continents. Photo Credit: Thinkstock Photos