Acquiring Genomes: A Theory of the Origins of Species

by Lynn Margulis, Dorion Sagan, Ernst Mayr

Publisher: Basic Books
ISBN: 0465043917

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From Booklist

A challenger of the orthodox "neo-Darwinist" interpretation of evolution, microbiologist Margulis has made her professional mark touting an alternative: symbiogenesis. She and coauthor (and son) Sagan have presented their ideas in earlier popular works (What Is Life?, 1995), but never as vigorously as in this volume. Essentially, the debate between neo-Darwinists and Margulis hinges on the definition of a species, and the manner in which a new one appears. To Margulis and Sagan, the neo-Darwinist model, which asserts random gene mutation as the source of inherited variations, is "wildly overemphasized," and to support their view, they delve deeply into the world of microbes. They detail the anatomy of cells with and without nuclei, positing a process of genome ingestion that creates a new species. Surprisingly, the upshot of Margulis' theories is the rehabilitation of Jean Baptiste de Lamarck, whose theory that supposedly acquired traits are hereditary has been ridiculed for 150 years. Polemical and provocative, Margulis and Sagan's work should set many to thinking that evolution has not yet been completely figured out.

From Book News, Inc.

Speedy, determined bacteria, and expert protist architects, caught between an tectonically active Earth and an energetic sun, engage in wars, alliances, bizarre sexual encounters, mergers, truces, and victories to create species. Random mutations and an omnipotent deity, say Margulis (geosciences, U. of Massachusetts-Amherst) and New York City science writer Sagan, played no part.

Book Description

From one of the great iconoclasts of modern biology, an original, accessible work that sets out, for lay and scientific readers alike, a new theory of how species begin.

In this groundbreaking book, Lynn Margulis and Dorion Sagan present an answer to one of the enduring mysteries of evolution--the source of inherited variation that gives rise to new species. Random genetic mutation, long believed to be the main source of variation, is only a marginal factor. As the authors demonstrate in this book, the more important source of speciation, by far, is the acquisition of new genomes by symbiotic merger.

The result of thirty years of delving into a vast, mostly arcane literature, this is the first book to go beyond--and reveal the severe limitations of--the "Modern Synthesis" that has dominated evolutionary biology for almost three generations. Lynn Margulis, whom E. O. Wilson called "one of the most successful synthetic thinkers in modern biology," and her co-author Dorion Sagan have written a comprehensive and scientifically supported presentation of a theory that directly challenges the assumptions we hold about the variety of the living world.

Book Info

Authors present an answer to one of the enduring mysteries of evolution--the source of inherited variation that gives rise to new species.

About the Author

Lynn Margulis, Distinguished University Professor in the Department of Geosciences, University of Massachusetts, Amherst, is a member of the National Academy of Sciences and a recipient of the 1999 Presidential Medal of Science. She lives in Amherst, Massachusetts. Dorion Sagan is the author of Biospheres and, with Dr. Eric Schneider, Into the Cool: The New Thermodynamics of Life. He lives in New York City.

Customer Reviews

Lynn Margulis has been a maverick all her life. Early in her career she shocked her biological colleagues by arguing that the mitochondria that power our cells and the chloroplasts that let plants transform solar into chemical energy once were free-living bacteria. As soon as scientists could isolate and decode the scraps of DNA in those vital organelles, they found that she was right. Margulis went on to develop her Serial Endosymbiosis Theory, which attempted to trace the development of all creatures with nucleated cells, from yeasts to humans, to a series of genetic mergers between different kinds of organisms. According to Margulis, all the familiar family trees of life, which show only diverging branches, are wrong. Ancient roots and current branches cross and merge to produce new species. To Margulis, nature is far more promiscuous and much more creative than most biologists dream.

Her new book, Acquiring Genomes: A Theory of the Origins of Species, extends and deepens that argument. Margulis sets out to prove that new species rarely if ever appear as the result of mutation, isolation, genetic drift, or population bottlenecks--the meat and potatoes of neo-Darwinism. Instead she maintains that the major engine of evolutionary change, the source of most of the new forms that natural selection edits, is symbiogenesis--the acquisition of whole genomes as the result of symbiotic associations between different kinds of organisms. (Knowing that some people will seize on her thesis as an attack on the theory of evolution as a whole, Margulis makes it clear that she fully supports Darwin's great discovery of the mechanism of natural selection. She simply thinks that neo-Darwinists have failed to recognize the enormous creative power of genomic mergers.)

Readers who are familiar with Margulis' earlier works will recognize her vivid, personal and sometimes impressionistic writing style. I found this book, co-authored by her son, Dorion Sagan, to be clear and accessible. Starting with Chapter 9, where Margulis presents her latest ideas on the symbiotic origin of the nucleus itself, things get a bit more technical. Margulis makes every effort to help readers through the thicket of important, but at times tongue-twisting terms, and supplements explanations in the text with an excellent glossary. Margulis also presents the findings of several other researchers whose work supports or relates closely to her own.

Readers may or may not close the book convinced that Margulis is right and the neo-Darwinists are wrong. But they will come away with a vastly deeper understanding of the pervasive nature and power of the microbial world, and of symbiosis. Margulis reveals a hidden side of nature, in which microbes have generated most if not all of life's metabolic machinery, in which vastly different life-forms consort in a myriad of ways, and in which the acquisition of entire genomes provides the raw material for great evolutionary leaps. Anyone with a deep interest in biology will gain important insights from "Acquiring Genomes."

Robert Adler, author of Science Firsts: From the Creation of Science to the Science of Creation (Wiley & Sons, 2002).

In Acquiring Genomes, authors Lynn Margulis & Dorion Sagan collaborate to present a fascinating theory regarding the origins of species as they probe Charles Darwin's original ideas of evolution, and then taking them a step further in identifying the source of inherited variations that give rise to new species. The authors cogently argue that random mutation is not the main factor in such changes: more significant is how new genomes are obtained by symbiosis. Lynn Margulis & Dorion Sagan is highly recommended as a compelling, attention involving survey offering new insights based on meticulous research.

Acquiring Gnomes is an attempt to support the theory of symbiogenesis, the idea that organisms evolve by exchanging genes and as a result of symbiosis relationships, such as lichen. The authors are the leading experts in the field of symbiosis, and this shows in this well done work. The major strong point of the work is it explains in detail what biologists have known for years but often do not admit publicly, namely that evolution by the accumulation of small mutations has not been supported by either laboratory or field research. The authors also show that Darwin has been almost a god for over a century, yet his work was neither original (and he failed to credit those he plagiarized his ideas from - see p. 27) and his classic 1859 book The Origin of Species is "laced with hesitancies, contradictions, and possible prevarication" (p. 26). Having shown neo-Darwinism is now effectively dead, the authors make an excellent case for their own theory of the origin of species. The only problem is they demonstrate that many lower level organisms have probably exchanged genetic material throughout history, yet this does not explain its origin, only its spread. We are still left with the question "where did the genome information come from in the first place?" It may be best to admit that we do not know (and present theories do not explain this problem) so that future scientists are encouraged to look for the source instead of discouraging research by teaching students that we know the source when we do not. As a college teacher for over 35 years now, in my classes I stress what we do not know in my field (molecular biology) with the hope that my students may be inspired to find some of the answers. This book is a good place to begin. The authors also show that anyone who questions Darwin "are often dismissed as if they were Christian fundamentalist zealots or racial bigots" (p. 19). This is tragic.