Sewall Wright's active life spanned the development of genetics from a new discipline when the principles of inheritance were still being elucidated to the technology of recombinant gene construction and insertion. He was one of the major pioneers of population genetics, which gave a quantitative basis to the studies of evolution, of variation in natural populations and of animal and plant breeding. He contributed most significantly to methods and ideas over a long period, indeed his four volume treatise was written long after he formally ‘retired’ and his last paper (211) was published a few days before his death at the age of 98. In the field of population genetics Wright developed the method of path coefficients, which he used to analyse quantitative genetic variation and relationship, but which has been applied to subjects as diverse as economics, the ideas of inbreeding coefficient and
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-statistics which form the basis of analysis of population structure, the theory of variation in gene frequency among populations, and the shifting balance theory of evolution, which remains a topic of active research and controversy. Wright contributed to physiological genetics, notably analysis of the inheritance of coat colour in the guinea pig, and in particular the epistatic relationships among the genes involved. There was a critical interplay between his population and physiological work, in that the analysis of finite populations on the one hand and of epistatic interactions on the other are the bases of Wright’s development of the shifting balance theory. A full and enlightening biography of Sewall Wright which traces his influence on evolutionary biology and his interactions with other important workers was published recently (Provine 1986) and shorter appreciations have appeared since his death, notably by Crow (1988), Wright’s long-time colleague. This biography relies heavily on Provine’s volume, and does no more than summarize Wright’s extensive contributions. Many of his important papers have been reprinted recently (1986).
Reconstructing the shifting balance theory in a GA: taking Sewall Wright seriously
