Your life stems from a single cell. Yet within the trillion of cells that make up your body lies a fundamental conundrum. Each cell contains identical DNA, yet muscle cells are very different from skin cells; blood cells are very different from brain cells. How does each of your cells ‘know’ exactly what to do? And when? And where? How do your heart cells start beating? How can your eye cells help you see the world around you? Can we use our understanding of how stem cells transform into specialised cells to build new body parts? What can we learn from animals that can regenerate their limbs? And what are the implications of tinkering with the fabric of life?
Yes. But so am I. And so is the mouse that we share 99% of our genes with. As our DNA replicates, mutations arise. Sometimes they can be catastrophic, but sometimes they confer a huge advantage. Falcons have eyes that allow them to see for miles, but ants are virtually blind. How come? How are developmental processes altered over evolutionary time to produce novel structures and, ultimately, new species? The history of life revolves around survival of the fittest ‘mutant’. As we understand more about mutations it could help us devise new treatments for genetic conditions. But are we prepared to genetically engineer humans?
Every living thing – humans, animals, plants or a single cell – eventually dies, but why? How do cells know when to die? What controls the ageing process and could we ever halt it? Developmental biology and genetics give us new insights into how cells work and what happens when genes switch on and off. Can we use this knowledge to improve or even extend life? And what are the ethical issues if we do? Would you really want to live forever?