Chiasma redistribution in bivalents carrying supernumerary chromosome segments in grasshoppers

Abstract

Four supernumerary chromosome segments showing different locations in the chromosomes and different C-banding reactions are studied in three grasshopper species in relation with chiasma distribution in the bivalents which carry them. The presence of any of these extra segments leads to a chiasma redistribution in the carrier bivalents, so that such a chiasma is formed preferentially in the furthest chromosome regions from the extra segment. This effect of the four supernumerary segments is independent of both their location on the chromosome and their C-banding reaction. © 1985 The Genetical Society of Great Britain.