Chapter

Polyploidy

Volume 13 of the series Basic Life Sciences pp 341-378

Evolutionary Implications of Polyploidy in Amphibians and Reptiles

  • James P. BogartAffiliated withDepartment of Zoology, University of Guelph

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Abstract

In plants, Polyploidy is recognized to be a wide-spread phenomenon and of considerable practical and evolutionary importance, whereas polyploid animal species have been relegated for the most part, to insignificance in terms of their existence or evolutionary importance. Evolutionary and genetic authorities have adhered mostly to Müllers’s 1925 (1) contention that sexual imbalance in polyploids would not permit bisexual polyploids to exist as natural entities in animals as they do in plants, which are capable of vegetative reproduction. Asexual polyploids are also condemned, in animals, by the commonly held, and mathematically “proven” (2) viewpoint that this method of reproduction reduces genetic recombination and is tantamount to phylogenetic suicide (3–5). It is evident, however, that an increasing number of polyploid amphibians and reptiles are being encountered in natural populations living in North America, South America, Europe, Asia, and Africa. To ignore their existence or to pass judgement on their evolutionary significance without adequate study is incomprehensible. In spite of the theoretical dogma surrounding animal polyploids, there is a growing bank of data which suggests that naturally occurring animal polyploids may play an interesting and significant role in population genetics and speciation.