Cytological Observations on the Strandedness of Mammalian Metaphase Chromosomes

Abstract

Metaphase chromosomes per se are unsuitable for the study of structure because of their highly condensed state. A combination of hypotonicity, chelation using either sodium citrate or versene, and air-drying of the unfixed chromosomes allows a large quantity of intact, condensed metaphase chromosomes to spread for the study of structure. Chromosomes prepared by these techniques can be readily uncoiled by various reagents. Since the starting material is the visible condensed metaphase chromosome, material obtained after treatment is mostly likely to be chromosomal.