Beyond Inheritance: Our Ever-Mutating Cells and a New Understanding of Health

Science journalist Khamsi demonstrates in this accessible debut examination that one’s DNA is not a static set of instructions but a continuously mutating blueprint. Understanding the genetic variation that emerges within the body over time, she argues, is essential for improving health outcomes. The adult human body is made up of approximately 30 trillion to 40 trillion cells that are constantly dying and being replaced by new ones, Khamsi explains. Mutations occur as DNA replicates when cells divide, with some estimates showing trillions of new mutations per day. While many mutations are benign, others can cause serious complications, including cancer, cognitive problems, and immune disorders. As Khamis shows, understanding these mutations can lead to innovative treatments for diseases, like adaptive therapy, a precise drug-dosing method intended to slow the rate of mutations that allow cancer cells to survive. Elsewhere, Khamsi discusses how some conditions long thought to be inherited from parents, such as autism, Down syndrome, and endometriosis, may arise from mutations that occur during fetal development. Through lucid language and enlightening case studies, Khamsi makes a persuasive case that “we’re mistaken if we limit ourselves to thinking of genetic diseases as always inherited.” Readers will benefit from this comprehensive look at the dynamic nature of DNA. (Apr.)