The gene variant APOE4 is finally giving up some of its secrets, how putting dead trees underground could make carbon sequestration cheap and scalable, and the latest in our series of books on an optimistic future   First up this week, Staff Writer and Editor Jocelyn Kaiser joins host Sarah Crespi to discuss APOE4, a gene linked with a higher risk of Alzheimer’s disease. They talk about new research into why APOE4 might be a good target for preventing or treating this dreaded neurodegenerative disease.   Next, Ning Zeng, a professor in the Department of Atmospheric & Oceanic Science and at the Earth System Science Interdisciplinary Center at the University of Maryland, joins the show to discuss an unusual approach to carbon sequestration and a very old piece of wood. He talks about how an unearthed 3000-year-old log that has held on to most of its carbon is pretty good proof that we can efficiently put carbon underground at low cost by burying trees.   Finally, we have the latest in our series of books on a future to look forward to. Books host Angela Saini talks with Peter Coveney and Roger Highfield, the two authors of the book Virtual You: How Building Your Digital Twin Will Revolutionize Medicine and Change Your Life.   This week’s episode was produced with help from Podigy.   About the Science Podcast Episode page: https://www.science.org/doi/10.1126/science.z8oerdq   Authors: Sarah Crespi; Jocelyn Kaiser; Angela Saini Learn more about your ad choices. Visit megaphone.fm/adchoices