A foot in each world

Captivating Life: A Naturalist in the Age of Geneticsby John C.Avise Smithsonian Institution Press, 2002.$24.95 hbk (222 pages) ISBN 1 56098 957 2Throughout the history of biology, there has been an uneasy coexistence between two very different traditions – a field-orientated one with its emphasis on natural history, and a laboratory-based one with its emphasis on experimentation. Tensions between these two traditions intensified after the discovery of the structure of DNA spurred the rise of molecular genetics. In his autobiography [1xWilson, E.O. See all References][1], Edward O. Wilson documented these ‘molecular wars’ as they affected Harvard's biology department during the 1950s. Although molecular wars continue to rage, or at least smolder, in most biology departments, a new synthesis has emerged in recent decades. With increasing frequency, molecular genetic techniques are being used to address ecological and evolutionary questions, leading to the creation of new fields such as molecular ecology and phylogeography. John Avise, who has been at the forefront of the creation of these fields, discusses their maturation and his own in his autobiography, Captivating Life.Avise's first passion was natural history. Growing up in Michigan, he developed a particular fondness for birds and fossils. During summers as a teenager, Avise assisted Harry Pederson filming undersea life in the Bahamas. Here, Avise learned the ‘concept of observational natural history in its own right, in which novel secrets of science might be learned with suitable diligence’. Avise's maturation as a natural historian was also substantially influenced by his reaction to the Vietnam War. He shares an illuminating excerpt from the 1970 letter he wrote as part of his application for Conscientious Objector status wherein he explains his philosophy about environmentalism and the war.Avise was impressed by the power of genetic tools as a graduate student. Under the tutelage of Robert Selander, then at the University of Texas, Austin, Avise used the then-new technique of allozyme electrophoresis to examine the genetic variability of cave- and surface-dwelling populations of fish in the genus Astyanax. In less than a year, he collected sufficient data for a Master's thesis that was quickly turned into a classic paper [2xEvolutionary genetics of cave-dwelling fishes of the genus Astyanax. Avise, J.C and Selander, R.K. Evolution. 1972; 26: 1–19CrossrefSee all References][2]. Among other things, Avise found that surface populations have markedly greater genetic diversity than do cave populations. For his doctorate, Avise joined Francisco Ayala's lab at the University of California, Davis, and examined patterns of genetic diversity among species of minnows and sunfish. Although there are many more species of minnow than of sunfish, species within each group showed comparable levels of divergence. This pattern was interesting in that it was consistent with phyletic gradualism, the claim that morphological change generally occurs gradually and within lineages. The pattern was seemingly inconsistent with the competing claim of punctuated equilibrium, which states that morphological change occurs in fits and starts and generally coincides with the splitting of species.Although working with very diverse taxa, Avise's research program has been unifying. Not only did he bridge the gap between the lab and the field, Avise also helped to bridge the gap between population genetics and phylogenetics by focusing on phylogenies below the species level. Avise was one of the driving forces in investigating how geographical features influence phylogenetic clustering. He also attempted to forge a consilience between the seemingly antithetical biological species concept (which emphasized reproductive isolating barriers) and the phylogenetic species concept (which emphasized diagnosably distinct character states) [3xPhylogenetics and the origin of species. Avise, J.C and Wollenberg, K. Proc. Natl. Acad. Sci. U. S. A. 1997; 94: 7748–7755Crossref | PubMed | Scopus (220)See all References][3]. Perhaps the diversity of taxa and questions he has worked on helped Avise to see the conceptual unifications.Captivating Life provides a rare glimpse into the thoughts of an active researcher in mid-career. Avise not only discusses issues related to science, but also those of lab management and graduate student training. For instance, Avise strongly disagrees with the conclusion by the National Research Council (NRC) that the US grants too many PhD degrees ‘relative to its needs’ in the biomedical sciences. Instead, he believes that the current and looming environmental crises and the technological breakthroughs in genetic engineering require the training of many more biologists in both genetics and environmental biology. Although my personal opinion is closer to that of the NRC, Avise's defense of his position is well considered and worth reading.Science, as Avise concisely and accurately describes, is ‘…a principled manner by which phenomena are explored. The epistemological hallmarks of science are objectivity, critical open-mindedness and the ruthless evaluation of alternative hypotheses against evidence’. Avise's autobiography also shows that the science of life, from natural history to molecular genetics, can be captivating.