It is now nearly a quarter of a century since N.T.J. Bailey's book Introduction to the Mathematical neory of Genetic Linkage appeared. It brought together in a single volume the mathematical theory of both genetic linkage and chromosome mapping. But even though Bailey's book contained a brief section on the special problems arising in the measurement of linkage in man, much of that section was already out of date at the time of publication. Since then, furthermore, many research papers have been written in the area of human genetic linkage, both methodological and substantive. Over the last dozen years there have been eight International Workshops on Human Gene Mapping. Because man is a nonexperimental organism, the appropriate methods of analysis are quite different from those appropriate to the study of Drosophila, for example. Ott's book, with its dual aim of serving as a guide to the practitioner in the human field and of presenting a unified likelihood approach to linkage analysis, is thus a timely contribution.
The book starts with two brief introductory chapters on basic genetics and genetic markers. Practitioners of linkage analysis will find these chapters a useful review, but anyone who is not already familiar with the subject will be well advised to go elsewhere for an introduction to these concepts. Linkage, for example, is first defined as a purely genetic phenomenon and only later is the physical basis for it described. The unnecessarily cumbersome notation for alleles recommended in the International System for Human Gene Nomenclature is used to start with, but by page 16 disappears, reappears on page 17, and throughout the book it is inconsistently used until finally, in Chapter 10, it is given up altogether. Those who have lived through the changing nomenclature will probably smile at the unnecessary asterisks that alternately appear and disappear.
The heart of the book starts with Chapter 3, "The Likelihood Method of Linkage Analysis." This is followed by a short chapter on numerical methods, and then by three chapters that deal with complicating factors in linkage analysis: heterogeneity of the recombination fraction, model misspecifications, and variable penetrance. These chapters bring together much of the new methodology that has been developed in the last two decades, together with sound, practical advice for performing linkage analyses on pedigree data. The explanations of the derivations are not always clear,