Kin: How We Came to Know Our Microbe Relatives

Since Darwin, people have speculated about the evolutionary relationships among dissimilar species, including our connections to the diverse life forms known as microbes. In the 1970s biologists discovered a way to establish these kinships. This new era of exploration began with Linus Pauling's finding that every protein in every cell contains a huge reservoir of evolutionary history. His discovery opened a research path that has changed the way biologists and others think about the living world. In Kin John L. Ingraham tells the story of these remarkable breakthroughs. His original, accessible history explains how we came to understand our microbe inheritance and the relatedness of all organisms on Earth. Among the most revolutionary scientific achievements was Carl Woese's discovery that a large group of organisms previously lumped together with bacteria were in fact a totally distinct form of life, now called the archaea. But the crowning accomplishment has been to construct the Tree of Life-an evolutionary project Darwin dreamed about over a century ago. Today, we know that the Tree's three main stems are dominated by microbes. The nonmicrobes-plants and animals, including humans-constitute only a small upper branch in one stem. Knowing the Tree's structure has given biologists the ability to characterize the complex array of microbial populations that live in us and on us, and investigate how they contribute to health and disease. This knowledge also moves us closer to answering the tantalizing question of how the Tree of Life began, over 3.5 billion years ago.

About the Author :
John L. Ingraham is Professor of Microbiology, Emeritus, at the University of California, Davis.

Review :
In a delightfully personal yet accurate style, Ingraham describes the events and personalities that brought us the ‘Tree of Life,’ the representation that encapsulates the relatedness of all organisms of Earth. Readers will be educated while they are entertained as they explore fascinating aspects of life discovered through the study of our microbial relatives. One of the grandest achievements of modern biology has been the unraveling of the relationships among the many kinds of life and the determination of the course of evolution, a great tree of all life. In Kin, prominent microbiologist John Ingraham traces the scientific developments that led to this achievement and some of its ramifications. Along the way, with many personal anecdotes about scientists involved, Ingraham unfolds the history of microbiology and molecular biology, the development of genetic technology, and ideas on the origin of life. Kin is a highly readable account of a remarkable period of scientific progress in biology. Charles Darwin knew microbes as ‘infusoria,’ and left them off his partial tree of life — little dreaming of how they dominate it, or of their intimate relationship with humanity. That kinship, reveals microbiologist John Ingraham in this succinct scientific chronicle, began to emerge in the 1960s and 1970s with revolutionary findings such as Carl Woese’s discovery of archaea. Ingraham deftly traces the rise of relevant fields, and highlights landmark research on the gut microbiome, the putative origins of life in oceanic hydrothermal vents and more. Darwin included a single figure in On the Origin of Species: a sketchy Tree of Life, showing how the teeming variety of creatures derive from a single common ancestor. Today, explains John Ingraham, we have fleshed out the picture and can demonstrate in detail how ‘we are all kin…from the smallest bacterium to the largest blue whale.’ He describes the process of discovery that revealed the sole three branches on the tree: the recently discovered archaea, the bacteria and the eukaryotes, which include everything from protozoa, algae and fungi up to humans. Our new knowledge of the tree’s structure can help us to understand how bacteria on, in and around us cause disease; it may also offer clues about the origins of life. In simple and straightforward prose, Ingraham restores the true importance of one of the most revolutionary yet understated discoveries of the last century: that we all descend from, and are intricately linked with, microbial creatures. Ingraham’s narrative is a profound story about our true origins, remarkable in scope and multi-dimensional in ambition. This all-encompassing tale extends from the beginning of life on earth to the present day, and occasionally casts a glance at the future. Readers who expect to learn about our unicellular friends (and enemies) will also find an account of the beginning of life, the discovery of DNA, the quest to cure disease, a brief digression into gene editing, and a forecast of impending ecological disasters…Modest and revealing, Kin focuses our eyes on the invisible and unfamiliar—and thereby puts our own existence into perspective. The book offers a pluralistic account of our varied encounters with the manifold microbes around us. But as divergent as it may seem, this story is equally unifying. Stringing together insights from many disciplines, distant places, and different times, Ingraham delivers a living history that is unique and whole, and invites us to become a part of it. An intricately structured story that flows very well and shows how all these discoveries interlocked and influenced each other…It is not often that someone is willing or capable at the end of a long career to sit down and write a cogent eyewitness history of their discipline. That alone makes Kin a noteworthy and admirable achievement. Those curious to learn about modern microbiology would certainly enjoy hearing from one of its founders.