Somatic Association at Metaphase in Allium Triquetrum

Abstract

Over recent years an increasing amount of research has been directed towards an attempt at understanding the phenomenon of somatic homologous pairing (somatic association) i.e. the tendency for homologous chromosomes to lie closer together than would be expected on random chromosome distribution. Such pairing has been studied in both animal tissue (e.g. Froland and Mikkelsen 1964; Barton et al 1964, 1965; Ockey 1969), and plant tissue (e.g. Feldman et al 1966; Brown and Stack 1968, 1969; Sadasivaiah et al 1969; Wagenaar 1969), and has been seen at various stages of the cell cycle. One of the many still unanswered questions concerning this problem is what affect the formation of the metaphase plate has on chromosome association i.e. whether association increases or is disrupted during this phase. Hinton's (1946) work with Drosophila suggested that association was strongest at metaphase while Natarajan et al (1966, 1968), believed homologous pairing occurred throughout the cell cycle.