Nature genetic basis and evolution of the haemoglobin polymorphism inChironomus

Abstract

Chironomus larvae exhibit considerable haemoglobin polymorphism.Chironomus tnetans has 10 andC.pallidivittatus has 8 electrophoretically different Hb-chains. With the exception of one Hb-chain, all are species-specific. The hybrid which is fertile, shows the Hb-pattern of both parents. In the F₂ and subsequent generations, considerable chromosome rearrangements occurs. Since the chromosomes of the parent species can be distinguished in the polytene state, Hb-patterns can be correlated with specific chromosomal constitutions. All the species-specific Hbgenes are located on one chromosome. This finding suggests that the Hbgenes have evolved through multiple gene duplications. Different mechanisms for gene duplication are discussed.