Studies on the evolutionary relationships between hemoglobins in Chironomus pallidivittatus and C. tentsans. I. Isolation and immunological analysis of monomeric and dimeric hemoglobins.

The monomeric hemoglobins of Chironomus tentans and C. pallidivittatus have been isolated and separated into their respective components by gel chromatography on Sephadex G-75 and ion-exchange chromatography on DEAE-Sephacel. The amino acid compositions of the purified components are given. The sequence of the 30 N-terminal amino acid residues of one of the monomeric components (Hb I from C. pallidivittatus) was determined and found to be identical in almost all of its parts with the monomeric hemoglobins of C. thummi (CTT III and CTT IV). Antibodies against the monomeric hemoglobins Hb I and Hb IIc and the dimeric fraction were highly specific and no cross reaction between dimeric and monomeric hemoglobins could be demonstrated. The antibodies against the monomers crossreact with the monomeric hemoglobins CTT III and CTT IV of C. thummi. Taken together with genetic data, the immunological results indicate that divergence of monomeric from dimeric forms was an early event in the evolution of the various hemoglobins in Chironomus.