Chiasma distribution and centromere orientation in a spontaneous interchange in the grasshopper Chorthippus vagans

Abstract

One of 18 Chorthippus vagans males from a natural population was heterozygous for an interchange between the L1 and M4 chromosomes when examined cytologically. Chiasma distribution within multiple chromosome configurations and the relation between chiasma formation in the interstitial segments and centromere orientation were investigated. Our results confirm previous observations that adjacent-2 is the most common orientation in absence of chiasmata on the interstitial segments.Key words: Chorthippus, interchange, interstitial segments, chiasma distribution, orientation.