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Probability Models and Statistical Models in Genetics

with data. Whether an algebraic commentary is to be seen as the nourishing root, the supporting trunk, the protective bark, the flower, or the fruit, is likely to depend on the reader's background and established prejudices. Notwithstanding the stated aim of a simple account for the non-mathematical biologist, the reader needs either knowledge of integrals, exponentials, differential equations, and matrices, or a willingness to take these on trust. Sometimes the formulations are needlessly complex, as in handling the symmetrical relationship of dominance and recessivity without using both p and q when p + q = 1. This complexity has led to a misleading and erroneous crossover of the lines on figure 1.3. Some other graphs are difficult to follow, and rather roughly drawn. A computation leading to negative gene frequencies could have been omitted, or explained in more than three lines (p. 181). The book provides a useful numerical vade mecum to an extensive anthology of observations and experiments, mainly on butterflies, moths, and snails, and discusses various parameters of selection. However, due to the force and lucidity of E. B. Ford's 'Ecological genetics', the author has attempted a difficult task, and a calculus which restricts organisms to one locus, two alleles, and a large drift-free population undisturbed by inbreeding may seem of more value as a deductive than as a descriptive system. The author's scope is further limited by the nature of big effects for, by definition, these can be captured without weaving gossamer traps from differentials and variances. The use of gene, allele, and locus as synonyms adds a further simplification at the cost of reality. One serious logical trap into which Dr Cook invites further victims is the carrying out of significance tests to see if an effect is 'real', followed by an estimation procedure to see how big it is (chapter 9). This is following in distinguished footsteps, but is nevertheless a most serious and evident source of bias, guaranteed to make big effects bigger. The evidence for substantial selective forces hardly needs the help of concordant sampling errors. The production is good; the paperback good value, and, however difficult the challenge, a numerical treatment of a field rich in prose, intuition, and data is to be welcomed. The more advanced mathematical treatments are rarely germinal to the ideas, and can be bypassed without making the book useless to those biologists who prefer to restrict themselves to methods they can understand. For those who feel more secure with numbers than words, the book provides a good introduction well integrated with reliable data. There is a useful genetical and numerical glossary. J. H. EDWARDS