The meiotic consequences of spontaneous Chromosome breakage

Asymmetrical bivalents, both with and without free fragments, dicentric bridges and acentric fragments, bivalents with half chiasma and side-arm bridges have been found to occur in the meiosis of a number of species. It is argued that these anomalies constitute a common meiotic syndrome which is explicable in terms of varying patterns of spontaneous breakage and exchange. Moreover the association of the syndrome with meisosis suggests the possibility that the breakageexchange patterns reflect errors in chiasma formation.It is with considerable pleasure that we offer this paper to Professor J. Seiler, elder statesman of Cytology, in commemoration of his 80th birthday.