Imprinting: The Facts Ma'am, Just the Facts Genomic Imprinting Edited by Wolf Reik and Azim Surani Oxford: IRL Press (1997). 272 pp. $125.00

Historically, imprinting was identified in genetic crosses such complex disorders remains unknown. In this con-where different outcomes depended on whether the muta-text, a short discussion should have been incorporated tion was contributed by the mother or the father. The for an extremely active area of research on the genetics book presents many interesting human cases. For ex-of psychiatric diseases. I particularly enjoyed the specu-ample, inheritance of deletions of a region of chromo-lations of how genetic processes may be inherently vari-some 15 (15q 11–13) from the father leads to Prader-able or stochastic in occurrence. An interesting exam-Willi syndrome, whereas deletions in the same region ple, which is not quoted in the book, is the evidence for inherited from the mother cause Angelman syndrome. a genetically determined random component in specifi-These studies established that the proximal region of cation of human hand preference (Klar, Cold Spr. Harb. the long arm of chromosome 15 is subject to both pater-Symp. 61, 59–65, 1996). nal and maternal imprinting. Expression of several other In summary, this book presents marvelously succinct genes such as IGF2, KIP2, SNRPN, and IPW are also summaries on the current state of knowledge of genetics subject to imprinting. Defects in imprinting due to chro-and epigenetic etiology of human diseases. The field of mosomal recombination or the inheritance of both al-genetics—let alone the more esoteric field of epigenet-leles from one parent can also result in human diseases, ics—is usually so specialized that comprehension is ex-including some types of cancer. Although imprinting pected to be difficult to outsiders. However, the easy-was discovered because of the parent-of-origin effect reading style and the matching of each genetic principle on the expression of certain genes, similar to violations with a corresponding human disease conveys a sense of Mendel's rules, exceptions to the rule of parental of purpose, prodding one to continue reading the book effect on imprinting have been recently discovered. Im-to completion. The transition between chapters is partic-printing is likely to be one of the important mechanisms ularly smooth; consequently, one enjoys the seamless of regulating genes in a heritable fashion in order to flow in the progression of ideas. Being a short book, it maintain specific states of gene expression through mul-can be read in two to three sittings. A strong point of tiple cell divisions in somatic cells during development. the book consists of an up-to-date list of references: of More cases of monoallelic …