Abnormal mitoses in tetraploid yeasts

Abstract

1. The occurrence of tetraploidy in yeasts reported by us several years back finds confirmation in some recent reports regarding the existence of tetraploid Saccharomyces. Tetraploidy furnishes the possibility of an array of genetic combinations ignored up till now by Winge and Lindegren. 2. Photomicrographs are presented to illustrate normal and abnormal mitoses in a tetraploid. The origin of diploids, triploids, pentaploids and hexaploids are described. 3. Abnormal mitoses common in tetraploid yeasts offer possibilities regarding the origin of new types. Lindegren's belated admission that triploid and tetraploid yeasts do occur is a tacit admission of the accuracy of our criticism that since he and Winge analysed segregation in yeasts ignoring the possibility of polyploidy, their work was based on a fundamentally erroneous assumption.