Cytological Investigations in a Form of Allium Triquetrum Heterozygous in One Satellite Chromosome

Abstract

One of the most obvious morphological features by which certain chromosomes in a complement can be recognized is the satellite region produced by the secondary constriction associated with nucleolar organization. Normal Allium triquetrum is characterized by two pairs of homologous satellites. Aberrations involving the satellite are a frequently occurring form of chromosome mutation, usually resulting in the development of a heterozygous condition for the satellite concerned. The occurrence of a clone of A. triquetrum heterozygous for the more conspicuous satellite of the two was noted by Mr. G. K. Rickards. He suggested that this should be established definitely, and that some benefit would be derived from selfing the plants and then analysing the progeny. In anticipation of this Rickards carried out the selfing and sowed the progeny seeds. Once the satellite configuration became known it was thought that studies might provide some information regarding the type of mutation which had occurred and the mode of its inheritance.