SPECIES-CHARACTERISTIC AND SUBSPECIES-CHARACTERISTIC HEMOGLOBINS IN SOME TILAPIINE FISHES AND A COMPARATIVE-STUDY ON THEIR GLOBIN CHAINS

Haemoglobins of ten tilapia species of the genera Oreochromis, Sarothe rodon and Tilapia, three subspecies of the Nile tilapia, O. niloticus, and an artificial hybrid cross were analysed by isoelectric focusing aimed at characterizing the taxonomic value of these oxygen-binding mo lecules. Heterogeneous haemoglobin phenotypes were observed in haemoly sate samples of all the fishes, and species-characteristic as well as subspecies-characteristic patterns could be identified. F-1 hybrids we re distinguishable from pure parental specimens. Globin chain studies by AU- and AUT-PAGE systems confirmed the heterogeneity and species sp ecificity observed by isoelectric focusing of the tetrameric molecules . A total of eight different alpha-chains and eight different beta-cha ins were detected by AU-PAGE and species-characteristic globin chain v ariants were shown to occur in almost all species. Globin chain profil es of hybrid specimens were characterized by the presence of all paren tal globin chain variants.