The internal mechanics of the chromosomes II—Prophase pairing at meiosis in Fritillaria

Abstract

In the previous study I have described the changes in internal structure that the chromosomes undergo at mitosis and during the later stages of meiosis in Fritillaria . I have arrived at certain conclusions as to the relationships of these changes with the nuclear cycle. The most important of these are, first, that the spiral arrangement of the chromosomes is determined by a compensating molecular change; secondly, that there is a lag in the adjustment of the external form of the chromosome to its internal molecular stresses; and thirdly that paired chromosomes and chromatids will be caused by this adjustment to develop special spiral relationships which I have called relational coiling.