A LIGHT-MICROSCOPIC STUDY OF SOME TRANSLOCATIONS IN ASPERGILLUS NIDULANS

Abstract

A cytological investigation of the ascomycete, Aspergillus nidulans (Eidam) Winter, was undertaken to test the feasibility of using simple light-microscopial techniques to study chromosome aberrations for the correlation of chromosomes and linkage groups in this genetically well analysed fungus. Pachytene chromosome analysis was not possible, because the chromosomes are very small, do not spread well when squashed, and show very little structural detail. Some catenations were seen at first metaphase in translocation heterozygotes either as dense masses or, more rarely, as open rings. Lagging chromosomes were also seen at low frequency in both first and second anaphase and telophase in translocation but not in control material. The limited evidence from the study shows that meiotic chromosome behaviour in Aspergillus nidulans heterozygous for reciprocal translocations is probably similar to that in some higher organisms. However, the species is not suitable for detailed cytological analysis, at least by the techniques employed.