An Introduction to Molecular Ecology. Trevor J. C. Beebee and Graham Rowe. Oxford University Press, New York, 2004. 370 pp., illus. $49.50 (ISBN 0199248575 paper).
An Introduction to Molecular Ecology, by Trevor Beebee and Graham Rowe, is among the first books to describe how the methods of molecular biology are being used to revolutionize ecology. By combining molecular technologies with field studies, ecologists have created a new arena of investigation in which genetic markers are used to answer questions—about population dynamics, species diversity, adaptation, and conservation, for example—that until recently were beyond science's reach. The authors of An Introduction to Molecular Ecology are excited about this emerging field, and in their introduction they set an optimistic and energetic tone that they maintain throughout.
The book provides a comprehensive review of the area, and would serve as an excellent supplemental text for a general ecology class or as a stand-alone resource in a more advanced course focusing on the use of molecular methods in ecology. Because it explains difficult molecular terms in language that is easy to understand, the book would also be useful to members of the general public who are interested in ecology.
Trevor Beebee is a professor of molecular ecology in the School of Life Sciences at the University of Sussex, and Graham Rowe is a lecturer in the School of Biological Sciences at the University of Wales, Bangor, United Kingdom. The authors' backgrounds and expertise are in both ecology and molecular biology, and their excellent command of these fields allows them to present complex material (for example, genetics, genomics, and molecular methods) in a clear and concise manner. They are highly qualified to comment on the topics covered in the text and are sure to become known as experts in the new discipline.
The first chapter provides an introduction to molecular methods and techniques, highlighting methods—including DNA fingerprinting, polymerase chain reaction (PCR), and DNA sequencing—that have had a significant impact on experimental molecular biology and, in recent years, molecular ecology. Throughout the book, the authors discuss additional molecular technologies, such as microarrays and the identification of single-nucleotide polymorphisms, in the context of specific ecological topics. A more detailed description of relevant molecular methods and a glossary of terms are provided in an appendix. This organization permits readers who lack an extensive background in molecular biology to focus on the ecological discussion, yet allows them to consult explanations of specific molecular techniques as necessary.
Later chapters cover specific topics, such as behavioral ecology, population genetics, phylogeography, conservation genetics, and microbial ecology. The authors describe major scientific issues within these fields and cite studies that have used molecular methods to answer specific questions. In the chapter on behavioral ecology, for example, the authors review studies of species-specific male and female mating patterns, including mate selection, monogamy and promiscuity, reproductive success, and sexual competition. Beebee and Rowe describe several research projects that have made use of DNA fingerprinting to determine the paternity of individuals of various bird species, for instance. These investigations have allowed ecologists to identify some species as monogamous and others as polygamous on the basis of their genetics alone. Beebee and Rowe note that “one of the biggest revelations from molecular paternity analysis has been that many socially monogamous species are in fact polygamous in terms of mating behavior.”
Elsewhere in the same chapter, the authors demonstrate how DNA sequencing methods have improved our understanding of mate selection. Experimental work has shown that an individual's choice of mates is influenced by major histocompatability complex (MHC) genes. MHC molecules play an important role in the immune response, and having diverse MHC genes (high polymorphism) allows an individual to cope with a large number of pathogens. Both humans and mice select mates on the basis of smells associated with particular MHC genes; specifically, females choose mates with MHC genes unlike their own. This phenomenon, which has also been demonstrated in fish (Arctic char), supports the inbreeding avoidance hypothesis, which posits that females recognize kin and avoid mating with them on the basis of their MHC type. On the other hand, behavioral tests with the three-spined stickleback have shown that although a stickleback's choice of a mate is affected by MHC type, females choose males that have highly diverse MHC genes, rather than males that are simply unlike the choosing females in terms of MHC type. This observation supports the “good genes” hypothesis, which predicts that females will choose the healthiest males to mate with. MHC gene polymorphisms have also been used as genetic markers in studies of adaptive variation.
In another chapter, Beebee and Rowe demonstrate how powerful new molecular technologies such as DNA sequencing, PCR, and DNA microarrays have improved microbial ecology. With these techniques, ecologists have been able to identify microbial species more accurately and define genes involved in specific processes. DNA microarrays enable researchers to analyze thousands of genes at a time, and have been used to distinguish, for example, different strains of Pseudomonas bacteria in a complex sample. Microarrays are rapidly being constructed for numerous microorganisms.
Overall, the book contains helpful visual aids: each chapter has figures and tables that illustrate specific topics, as well as sidebars that highlight major points, and ends with a bulleted summary that reiterates the most important content. Original research studies are well documented in the reference section.
Beebee and Rowe's book will serve as a valuable resource for a diverse population of students and readers. It highlights topics that are relevant to ecologists, biologists, and environmentalists, and I am confident it will have a significant impact.
