Science Salon

In this dialogue with one of the best nature and science writers of our generation, David Quammen and Michael Shermer discuss his new book on the history of one of the most exciting revolutions in evolution and genetics that is unfolding before our eyes. In the mid-1970s, scientists began using DNA sequences to reexamine the history of all life. Perhaps the most startling discovery to come out of this new field—the study of life’s diversity and relatedness at the molecular level—is horizontal gene transfer (HGT), or the movement of genes across species lines. It turns out that HGT has been widespread and important. For instance, we now know that roughly eight percent of the human genome arrived not through traditional inheritance from directly ancestral forms, but sideways by viral infection—a type of HGT. In The Tangled Tree David Quammen chronicles these discoveries through the lives of the researchers who made them—such as Carl Woese, the most important little-known biologist of the twentieth century; Lynn