"It's the dawn of the twentieth century. Darwin has theorized that traits get passed down through generations, and Mendel has come up with a mathematical formula that predicts how traits reappear over time. But a key mystery remains: is there a recipe for living beings? If there is, where is it hidden? With the help of powerful new microscopes and x-rays, scientists peer ever closer into cells, searching for answers. They find chromosomes, tight coils of DNA, mutations that introduce new variations in species, and proteins that dictate how living things function. Walter Sutton observes that chromosomes come in pairs. Nettie Stevens discovers the X and Y chromosomes that define biological gender. And Rosalind Franklin, James Watson, and Francis Crick compete to be the first to understand DNA's structure. But is it proteins or DNA that carry the secrets to life's blueprint? In Birth of Genetics, Joy Hakim, author of the best-selling series A History of US, continues charting the path of human discovery as scientists race to unravel our genes and the mysteries they hold"-- Front flap of cover.