Your investigation begins with the independent discoveries of genes and of DNA in the mid-1800s—which were not understood to be related for almost a century! Gregor Mendel, an Austrian monk, used pea plants to discover what discrete units of inheritance are, later called genes. Meanwhile, biochemist Friedrich Miescher extracted a sticky substance from the nuclei of cells later called DNA. Follow both trails into the 20th century, as chromosomes are discovered and the realization finally begins to dawn that genes and DNA may be related.
Join the quest to understand the molecular biology of the gene with the famous blender experiment, which showed that DNA, not proteins, transmit genetic information. Then look at five scientists who competed to solve the mystery of DNA’s structure, including Rosalind Franklin and a team of rookie investigators who stumbled embarrassingly in their first attempt: American James Watson and Englishman Francis Crick.
Enter the home stretch in the race to find the structure of DNA. With eminent chemist Linus Pauling leading the pack, longshots James Watson and Francis Crick got a key clue from rival investigator Rosalind Franklin—without her knowledge. Meanwhile, Cold War politics delayed Pauling. Analyze the reasoning that led Watson and Crick to their 1953 breakthrough, and consider why Franklin didn’t beat them to it.
Because DNA is only a blueprint, the discovery of its double helix structure was just the beginning. Trace the next big step: understanding how DNA synthesizes proteins through the intermediary of RNA. Here again, a dark horse researcher—Marshall Nirenberg—made the crucial breakthrough. Then see how DNA fingerprinting became possible in the 1980s, and study how two baffling crimes were solved using this technique.
Cover the “Manhattan Project” of DNA: the Human Genome Project to sequence all three billion base pairs of human genetic material. Two separate teams, led by Francis Collins and Craig Venter, competed bitterly to reach this costly goal, which required new technologies and controversial methods. Examine the politics and unexpected legacy of this effort, which was declared complete in 2003.
The decoding of the human genome paved the way for Project ENCODE, designed to identify functional elements in the genome. Focus on examples that are central to human culture, such as language. Probe the foxp2 gene that appears to play a role in speech, together with other genes. Consider the role of mutations and nature's gene splicing in boosting our brain and cognitive abilities.
Investigate the curious career of microbes in our bodies—not just the ones that make us sick, but more crucially, those that get incorporated into our DNA, driving evolution in unpredictable ways. For instance, the placenta that makes most mammals distinct from egg-laying animals appears to be an adaptation derived from an invasive virus. Learn why 8% of our genome is viral in origin.
Every cell in the human body has essentially the same DNA, yet cells behave very differently, partly due to epigenetics. In epigenetics, the DNA genetic sequence remains constant, but the activity of that sequence changes as genes get switched on and off. More surprising, epigenetics also explains how the inheritance of traits can be influenced by environmental factors, such as health issues in the children and grandchildren of famine survivors.
In the wake of the Human Genome Project, scientists were able to chart our shared heritage with a multitude of species. Most startling was evidence of breeding between modern humans and Neanderthals in the deep past, with a small percentage of Neanderthal DNA present in major human populations today. Peer into the human genome to read these and other clues about our multifaceted history.
DNA has solved age-old mysteries about prehistory: Where did humans originate? When did we first start wearing clothes? How did the agricultural revolution spread? Also delve into historical questions that DNA has answered, involving figures such as King Tut, Genghis Khan, Thomas Jefferson, and King Richard III. Consider Abraham Lincoln to ask where we draw the line in reading genetic secrets from the past.
Investigate the first precision technique for genetic engineering, CRISPR, heralded as holding the potential for science fiction-like manipulation of the human genome. Trace the history of CRISPR-based techniques from a coastal salt marsh, to the biochemistry lab at a yogurt plant, to top research universities, pharmaceutical firms, and the fight over patents. Consider the potential for abuse of this powerful tool.
Look at the genetic basis for certain diseases and how personalized genetic medicine might be customized to the hidden histories that each of us have written in our DNA. Discover what makes the challenges so daunting and focus in particular on the different mechanism behind different cancers, and how genetics helps us disentangle the differences. Ponder what new insights into the workings of DNA may be next.