INVERSION POLYMORPHISM IN CHIRONOMUS STAEGERI LUNDBECK

Abstract

Populations of Chironomus staegeri are polymorphic for inversions in six chromosome arms. Many of these inversions do not conform to Hardy-Weinberg expectation, often with a significant deficiency of heterozygotes. Many combinations of the inversions two-at-a-time show a significant deviation from random assortment. Often this is due to the occurrence together in the same individual of rare sequences, but others, such as the association of sequences A1 and C1, A2 and C2, and A2 and B4 appear to be real effects.There is a marked dimorphism in the inversion sequences present in populations from deep water and those from shallow water in the northeastern U.S.A. and Canada. This may be associate..