Mapping G-bands on human prophase chromosomes.

OHNUKI's method for demonstrating coils in human metaphase chromosomes also reveals a fine G-band pattern on prophase chromosomes of sufficient clarity to justify an attempt at mapping. Maps are provided for each chromosome to show the maximum number of prophase bands observed, and an intermediate stage in chromosome contraction, tracing the pathways of apparent band fusion as the cell progresses to metaphase, is presented. The prophase bands on many chromosomes tend to occur in distinct groups, the members of which ultimately merge to give the dark G-bands of metaphase chromosomes. Every G-band of the standard metaphase chromosomes. Every G-band of the standard metaphase pattern is compounded from two or more prophase bands. In at least contracted prophase chromosomes examined, some bands are seen which have no obvious metaphase counterpart. There are marked similarities between banded prophases and the chromoomere pattern seen at meiotic prophase. However, since chromosome contraction is a dynamic process, agreement between maps will be expected only for corresponding degrees of chromosome contraction.